brazilian male reidi not eating

Dear Tom:

I’m sorry to hear about the eating problems that your male Hippocampus reidi has developed. This type of feeding difficulty is known as weak snick. Since only one of your seahorses seems to be affected, I suspect that the loss of suction that characterizes weak snick is the result of a mechanical injury or muscular strain in this case, as explained in greater detail below. The following information will explain weak snick and related feeding disorders in more detail, Tom, as well as discussing treatment options.

Weak snick and related feeding disorders are usually due to either a mechanical injury or an infection affecting the seahorse’s hyoid bone trigger mechanism or the underlying musculature with which it generates the powerful suction that it uses when feeding. Such mechanical injuries can sometimes be caused by ingesting a foreign object while feeding, or the problem may be due to protozoan parasites that attack the gills and eventually affect the muscles that operate the buccal suction pump and/or the opercular suction pumps.

FEEDING DIFFICULTIES: WEAK SNICK, TRIGGER LOCK, & LOCK JAW

Seahorses suck! That’s a fact. Our amazing aquatic equines are supremely well adapted for suctorial feeding, which just means that their tubular snouts are designed for generating a powerful suction and slurping up small prey whole (Giwojna, Feb. 2004). Basically, their tubular mouths operate like slurp guns, a method of feeding that is often adopted by fish accustomed to taking prey from the bottom or plucking small crustaceans and larvae from the leaves of underwater plants (Evans, 1998). The anatomy of the seahorse’s head has evolved to accommodate this method of feeding (Giwojna, Feb. 2004).

For example, a tubular mouth is an advantage for suctorial feeding because it acts like a pipette and the narrow opening accelerates the inrush of water via the Venturi effect, thus maximizing the suction generated by the powerful head muscles (Giwojna, Feb. 2004). The seahorse’s oral or buccal cavity and gill chambers (opercular cavities) act as dual suction pumps that draw the water inwards with considerable force (Evans, 1998). Expansion of the buccal and opercular cavities causes a sudden drop in pressure within the mouth (Evans, 1998). The suction thus created allows the seahorse to suck up food through its slurp-gun snout faster than the eye can follow. In essence, the seahorse inhales its food in the blink of an eye, and cavitation caused by the sudden inrush of water traveling at tremendous velocity through the narrow snout and characteristic movements of its head and skull bones produce the distinctly audible "snick!" which announces the demise of its prey (Giwojna, Feb. 2004).

Every seahorse keeper is familiar with the seahorse’s "trigger," located at the underside of its jaws at the base of its throat, which moves downward sharply when the seahorse strikes, thereby expanding its oral (buccal) cavity and generating the suction to draw its prey inwards. This trigger is actually the seahorse’s hyoid bone, and it is pulled downward by contraction of the powerful sternohyoideus muscle that runs from the hyoid bone to the cleithrum (one of the bones of the pectoral girdle), which forms part of the seahorse’s bony exoskeleton (the cleithral ring) just behind its head (Evans, 1998).

The suction generated by the sudden downward contraction of the hyoid bone when a feeding seahorse "pulls the trigger" on its intended prey is greatly enhanced by the nearly simultaneous expansion of its gill chambers or opercular cavities (Giwojna, Feb. 2004). The additional suction thus created by the seahorse’s opercular pump is produced by contractions of the hyohyoideus muscles and dilator operculi muscles (Evans, 1998). The water pulled into the gill chambers this way is then expelled from the opercular cavity through a small pore. (This narrow opening accelerates the stream of water passing through it in the same way as its narrow tubular snout does.) The seahorse’s bony coronet evolved atop its head in part to provide solid anchorage and attachment points for the large muscles that operate its buccal suction pump and twin opercular suction pumps, which enable it to feed so efficiently (Giwojna, Feb. 2004). This is the perfect feeding mechanism for an ambush predator, and the seahorse is perfectly adapted for its role as the sniper of the seagrass jungle (Giwojna, Feb. 2004).

Of course the seahorse’s turreted, independently operating eyes are the perfect targeting system for this sophisticated feeding apparatus (Giwojna, Feb. 2004). Side-mounted, hemispherical eye turrets provide nearly 360 degrees of vision and allow the seahorse to look upwards and downwards (or forward and backwards) simultaneously in search of potential prey or possible predators (Giwojna, Feb. 2004). As soon as it detects a likely prey item, both eyes lock on it simultaneously and track it intently, thus providing excellent depth perception. This allows the seahorse to judge distances with remarkable accuracy as it draws a bead on its intended victim (Giwojna, Feb. 2004).

The hyoid bone is the trigger which fires the seahorse’s slurp-gun snout, and the moment its prey closes within striking distance, the powerful sternohyoideus muscle contracts and pull the trigger (Giwojna, Feb. 2004). The buccal cavity expands, followed the almost instantaneous contraction of the hyohyoideus muscles and dilator operculi muscles, which likewise expand the opercular cavities (Evans, 1998). The resulting drop in pressure creates a sharp inrush of water, which draws the prey irresistibly into the seahorse’s mouth (Evans, 1998). Once the prey has been sucked in, the mouth is closed. At this point, the buccal and opercular cavities are contracted and the excess water is forced out in a strong stream via the tiny opercular pores (Evans, 1998).

All this happens in an instant, faster than the eye can follow, and the powerful suction that is generated often macerates large prey (Giwojna, Feb. 2004). When the resulting debris is expelled from the gill chambers, it looks remarkably as if the seahorse is shooting smoke out of its ears, thus giving a feeding seahorse an uncanny resemblance to the legendary fire-breathing dragon (Giwojna, Feb. 2004).

However, when this remarkable feeding mechanism is injured or disrupted by parasites and/or secondary infections, a number of problems arise. Weak snick is an unusual affliction that results when a seahorse is unable to generate adequate suction to feed properly. Seahorses develop weak snick when their sophisticated feeding apparatus, or the muscles that operate it, are incapacitated as a result of injury or infection.

For example, I have often seen it in seahorses as a result of protozoan parasite infections (Amyloodinium, Cryptocaryon, Brooklynella, Uronema, etc.). I tend to suspect that’s the cause when the weak snick is accompanied by rapid respiration and labored breathing, or when more that one seahorse develops the condition, or when the weak snick victim’s tankmates are bothered by odd ailments such as "trigger lock," appetite loss, lockjaw, heavy breathing, or the first signs of snout rot, which can all be early indications of masked protozoan parasite infections (Giwojna, Dec. 2003). These organisms typically attack the gills first, from which they spread to the throat and mouth (oral or buccal cavity). As their numbers build up in the gills and they spread from within, invading the esophagus and oral cavity, symptoms such as rapid breathing, loss of appetite, weak snick, trigger lock, and snout rot begin to appear (Giwojna, Dec. 2003).

This is how I believe the disease progresses in such cases: the burrowing of the embedded parasites causes hyperplasia of the underlying tissue, and when sufficient numbers of them build up in the gills, we see the initial symptoms of respiratory distress, labored breathing, and huffing (Giwojna, Dec. 2003). During a heavy infestation, the parasites may attack the key muscles that expand the opercular cavity, or sheer numbers of the parasites can clog the gills to the extent that the opercular pump is impaired, resulting in weak snick due to a decrease in suction (Giwojna, Dec. 2003). In severe cases, this will eventually result in death by asphyxiation.

In less severe cases, the parasites will continue to spread from the gills into the throat, buccal cavity, and eventually the snout itself (Giwojna, Dec. 2003). When this happens, the irritation caused by the burrowing parasites and the hyperplasia of the infected tissue can cause loss of appetite or difficulty swallowing and the victim may go on a hunger strike (Giwojna, Dec. 2003). If the swelling and hyperplasia occlude the gills, throat and snout sufficiently to prevent the seahorse from generating adequate suction when attempting to feed, weak snick is the result (Giwojna, Dec. 2003). If the burrowing of the embedded parasites allows secondary fungal or bacterial infections to take hold, the seahorse can develop snout rot (Giwojna, Dec. 2003). When such secondary infection(s) affect the sternohyoideus muscle that controls the hyoid bone trigger mechanism, ailments such trigger lock, sticky trigger, or lockjaw result and again the seahorse is unable to feed (Giwojna, Dec. 2003). Weak snick can be caused in this way as well if the sternohyoideus muscle is affected to the extent that hyoid trigger still operates, but so feebly that the buccal pump can no longer generate sufficient suction to feed (Giwojna, Dec. 2003).

Another common cause of weak snick in many instances is a mechanical injury to the seahorse’s hyoid-bone "trigger" mechanism. This sometimes happens when a seahorse accidentally ingests a foreign object when feeding off the bottom. The offending particle is often a piece of gravel or crushed shell. When a hard, sizable foreign object such as this is ingested, it can lodge in the throat or snout, and the seahorse may have difficulty expelling it again. (The seahorse’s feeding mechanism is much better suited for sucking things in than spitting them out again.) When that happens, the seahorse is almost always able to clear the offending object eventually, but sometimes not before it causes considerable irritation or the repeated efforts to eject it cause a muscular strain to the hyoid trigger mechanism. The seahorse then acts as though it has a very bad sore throat. The suction it generates is weak and both the act of pulling the trigger and the act of swallowing appear to be painful. The seahorse feeds reluctantly or halfheartedly as a result, and may eventually stop feeding altogether. Such mechanical injuries can also open the door for snout rot.

Suspect a mechanical injury when the weak snick or sticky trigger is not accompanied by respiratory distress, when only one of your seahorses is affected and exhibiting unusual symptoms, or when you witnessed the seahorse struggling to expel a foreign object. In such cases, most often the problem clears up on its own after two weeks to two months as the injury heals. No treatment is necessary and the key to a successful outcome is keeping the patient eating while the healing takes place. That’s what treatment should concentrate on.

When these feeding difficulties arise, it’s a good idea to try tempting the affected seahorse with live adult brine shrimp. Seahorses suffering from weak snick induced by an injury may have better luck slurping up smaller, lighter, soft-bodied prey like brine shrimp; if so, that will be enough to keep them going while they heal. You’ll want to enrich the brine shrimp to maximize its nutritional value, and gutloading the shrimp with an enrichment product high in HUFA such as Vibrance is a good way to fortify it beforehand. Brine shrimp are filter feeders that will ingest whatever is suspended in the water with them, so all you need to do is add a pinch or two (or drop or two) of the enrichment formula to a small container of saltwater swarming with brine shrimp at least 30 minutes before you offer the shrimp to your seahorse.

Some hobbyists dealing with weak snick have had good success in coaxing the affected seahorse to feed by transferring the seahorse to a critter keeper or breeder net or similar enclosure that can hang within the main tank itself, and then adding a generous amount of live adult brine shrimp to the container. Within the enclosure, the affected seahorse does not have to compete with its tankmates for the live food, and it is easy to maintain an adequate feeding density within the confined space so that there is always a big juicy brine shrimp passing within striking distance of the hungry seahorse. Add one or two hitching posts within the critter keeper or breeder net so that your male can anchor in place and wait for a tasty brine shrimp to pass within easy reach, and give him an hour or two within the enclosure to eat him fill of the softbodied adult brine shrimp. You can monitor his progress from a nonthreatening distance away from the tank to see how she is doing. In most cases, the seahorse quickly becomes familiar with the routine of being transferred to the special enclosure at feeding time and associates it with tasty live foods and a full belly — positive reinforcements that make it a very nonthreatening, stress-free procedure for the affected seahorse — and, as a result, it may actually come to look forward to it after a few feedings. You can repeat this feeding process two or three times daily in order to fatten him up again, if your schedule allows.

In short, Tom, if the affected seahorse is experiencing respiratory distress or any other indications that suggest the problem could be due to protozoan parasites, please let me know right away and I will provide you with some detailed treatment options explaining how to treat your aquarium to eradicate such protozoan parasites. But if he is not showing any other symptoms other than a loss of suction when feeding, and his tankmates continues to thrive and eat normally, then you’re most likely dealing with a muscular strain or mechanical injury, and keeping your male eating by providing him with abundant softbodied adult brine shrimp to slurp up is probably the best approach to this problem.

In addition, please let me know what the current aquarium parameters for your seahorse tank are (i.e., the water temperature, salinity or specific gravity, and the ammonia, nitrite, and nitrate levels). Once I have this information, I will be able to advise you if there is any need to adjust your aquarium conditions to better suit the seahorses and make them more comfortable in their new surroundings. How large is your seahorse tank and how long has it been set up, Tom? Are there any tankmates besides the seahorses in the aquarium?

Best of luck keeping your male eating until his injury heals and the problem with weak snick resounds itself, Tom!

Respectfully,
Pete Giwojna

Dear Toni:

All of your aquarium parameters look excellent (the acceptable range for calcium is 350-450 mg/L or ppm, with natural seawater at 400 ppm for calcium), so it doesn’t appear that your water quality is an issue.

If your new packet of Piscine Energetics Mysis relicta are jumbo sized, and the switch to the bigger frozen Mysis coincides with the increased difficulty in slurping up and swallowing their food, it’s possible that the bigger prey items could be responsible for much of the problem. One thing I have noticed is that seahorses can sometimes be very selective when it comes to the size of the prey they prefer. The jumbo PE Mysis relicta are indeed quite large, and in it’s certainly possible that young seahorses may balk at the jumbos or have more difficulty swallowing them and need several snicks to get them down, simply because of their size.

Fortunately, the Piscine Energetics frozen Mysis relicta is now available graded for size. You can get the usual jumbo Mysis relicta or smaller Mysis and you may have better luck with the smalls since your H. reidi may prefer smaller prey. Some seahorses are very particular in that regard, and tend to reject food items that are significantly larger or smaller than their preferred range of prey. For example, I’ve seen some seahorses that rejected the smaller Hikari Mysis with great disdain, yet which greedily gulped down the jumbo Piscine Energetics Mysis relicta. On the other hand, I’ve had small seahorses turn up their snouts at the jumbo PE frozen Mysis because it’s too large for their liking, and attack the small Hikari frozen Mysis with great gusto.

If that’s the case with your H. reidi, Toni, you might try ordering some of the small Piscine Energetics Mysis relicta and feeding the larger ones to your other fish, or you can pick up a package of the much smaller Hikari frozen Mysis at your LFS for your seahorses instead. The Hikari Mysis is the smallest of them all and many pet stores carry the Hikari brand so it should be readily available. (I would recommend getting the Hikari Mysis in the flats, however, rather than the blister packs. The Hikari blister packs tend to yield frozen Mysis that is fragmented and broken in pieces, and seahorses often feed better on whole, intact frozen Mysis that retain their lifelike appearance rather than the bits and pieces from the blister packs. The Hikari frozen Mysis in the flats tends to be better preserved and less fragmentary…)

The Mini Mysis from H2O Life would also be another good choice for you under the circumstances, Toni, and I suggest offering your seahorses one of these brands of small frozen Mysis (or perhaps some soft-bodied adult brine shrimp) rather than the jumbo PE Mysis relicta to see if that produces better results. If your Brazilian seahorses are able to handle the smaller frozen Mysis or soft-bodied brine shrimp and eat them without difficulty, then all is well. If not, if they are still struggling to slurp up and swallow the small Hikari frozen Mysis or the Mini Mysis, then you should consider treating the seahorses and your main tank for protozoan parasites and ectoparasites. Please let me know what happens when you feed the smaller Mysis or live adult brine shrimp and we can go from there…

It’s also a good idea to begin enriching the frozen Mysis with Vibrance, just as you said, Toni. Not only will they Vibrance help keep your Brazilians looking their best and brightest and improve the nutritional profile of the enriched Mysis, it will also boost their immune systems and help them to resist disease.

I recommend the low-fat formulation in Vibrance 2 for mature seahorses that are not actively breeding (it will help prevent any potential problems with hepatic lipidosis or fatty liver disease), whereas the lipid-rich Vibrance 1 formula is best for juvenile seahorses that are rapidly growing and for mated pairs that are actively breeding and churning out brood after brood every month with clocklike regularity and need all the calories they can get.

Here are some of the Club’s additional suggestions for enriching frozen Mysis and some other feeding tips you may also find helpful, Toni:

Feeding Domesticated Seahorses

Their is no simple answer to how many frozen Mysis each of your seahorses should be eating per day. That depends on the size of the frozen Mysis, which varies considerably from brand to brand, the size of the seahorses themselves, and the size of their appetites, which is also quite variable from one pony to another, and a number of other factors. Mustangs and Sunbursts (Hippocampus erectus) of average size usually eat between 2-7 of the big Piscine Energetics Mysis relicta per feeding, but rather than trying to keep track of how many frozen Mysis each of your seahorses has eaten, it’s a better idea to check them for well-rounded abdomens after they have eaten a big meal and to observe their fecal production in order to make sure they are all getting enough to eat on a daily basis, as discussed below.

In addition to cycling your aquarium and setting it up to create an ideal environment for seahorses, you will also need to line up a good source of frozen Mysis before your seahorses arrive. Frozen Mysis is available in several different brands from many different sources. Gamma brand frozen Mysis is good, Hikari frozen Mysis is quite acceptable (although often fragmentary) as is San Francisco Bay brand frozen Mysis, the Mini Mysis by H2O Life is great for small seahorses, and Piscine Energetics frozen Mysis is no doubt the best in terms of nutritional content and quality control. Your local fish stores should carry one or more of these brands.

I have noticed that seahorses can sometimes be very selective when it comes to the size of the prey they prefer. For instance, the jumbo PE Mysis relicta are of course quite large, and in it’s certainly possible that young seahorses may balk at the jumbos simply because of their size.

Whatever brand of frozen Mysis you obtain, for best results, it’s a good idea to fortify it with Vibrance before feeding it to your seahorses. Vibrance is an enrichment formulation that was designed by a research team of nutritionists and fish biologists especially for use with frozen Mysis shrimp in order to meet the dietary requirements of seahorses, and it has been developed specifically to provide a long-term balanced diet for these unique fishes. Depending on which Vibrance formulation you use, it includes additional highly unsaturated fatty acids (especially the DHA Omega 6 DHA series), along with Vitamin C and essential minerals, in the proper proportions to further enhance the nutritional profile of the protein-rich frozen Mysis. Studies indicate the DHA it includes is essential for high survivability, nerve development, stress management, and proper reproduction. Vibrance is a bright red-orange powder that gets its characteristic color due to its high content of carotenoids, which are an abundant source of Vitamin A and act as natural color enhancers for yellow and red pigmentation. It is the only enrichment product that includes beta glucan as an active ingredient. That’s important because beta glucan is a potent immunostimulant that provides important health benefits for fish. Both Vibrance 1 and Vibrance 2 include beta glucan.

In order to enrich it, the frozen Mysis is carefully thawed out and rinsed well to remove any excess shrimp juices, and then a VERY light dusting of the Vibrance is added to the Mysis while they are still just a bit moist. The Vibrance is then gently worked into the frozen Mysis and it usually adheres very well. The end result should be whole, completely intact Mysis shrimp that have acquired a reddish tinge to their head or anterior end. In actual practice, there are probably as many different ways of successfully thawing and enriching frozen Mysis as there are aquarists that use them; most everybody works out their own method of preparing the frozen Mysis that works best for their needs and busy schedule.

In case you haven’t seen them already, here are the rest of the Club’s usual feeding suggestions, Toni:

Feeding Tips

In general, it’s a good idea to offer one morning feeding and one mid-to-late afternoon feeding, if possible, but there are no hard-and-fast rules when it comes to easy-to-feed, farm-raised horses. Some hobbyist prefer to give their seahorses two feedings a day, while others prefer to give them their quota of frozen Mysis in one big meal. As long as they get their fill, there is really no right or wrong way to go about this — just do whatever works bests for your seahorses and your schedule.

As you know, the feeding regimen that generally works best for most captive-bred seahorses is to provide each of them with 2-7 frozen Mysis relicta twice a day, enriched with Vibrance, and then to fast your seahorses entirely once a week. In other words, your seahorses should each be eating a total of around 4-14 frozen Mysis each day, depending on the size of the seahorse and the size of the Mysis. But those are just rough guidelines and there is a lot of variation in how much Mysis healthy seahorses eat each day.

A large seahorse naturally eats more than a smaller pony. And jumbo-sized Mysis will fill up a hungry seahorse faster than smaller shrimp. So a seahorse that’s scarfing up king-sized Piscine Energetics Mysis relicta does indeed need to eat fewer shrimp than a pony that’s dining on the tiny Hikari Mysis or the miniscule H2O Mini Mysis.

Aside from size, some of the other factors that determine how much a seahorse eats are water temperature, the age of the seahorse, and whether or not it is actively breeding at the moment. The warmer the water temperature (within the seahorse’s comfort zone), the higher it’s metabolism, and the more calories it needs to eat as a result. Young seahorses that are still growing rapidly typically eat more than mature seahorses that have reached their full growth. As you might expect, breeding pairs that are producing brood after brood every few weeks need to eat a lot because so much of their bodily resources go towards producing clutches of eggs or nourishing a pouch full of developing young.

So don’t get hung up trying to count every morsel every seahorse in your tank scarfs down. Just make sure all your seahorses have full bellies at the end of the day, as indicated by their well-rounded abdomens. After a good feeding, the seahorses belly rings should be flush or even slightly convex in cross section when viewed from head on. (We never want to see sunken, severely pinched-in abdomens on our seahorses! Concave belly rings are a sure sign of an underfed seahorse, with the sole exception of a female that has just transferred her eggs.)

So if you want to check whether your seahorses are eating well or not, don’t look at their profile — just examine them head-on and check out their gut. Their abdomens or belly plates should bulge out slightly or at least be flush with their flanks, not pinched in or sunken. In other words, when viewed from the back or from head-on, the cross-section of their abdomens should appear concave "( )" or flush "l l" rather than concave ") (" or pinched in.

Feeding Frozen Mysis

(1) Tips for thawing and enriching frozen Mysis.
In order to prevent wastage and obtain the maximum benefit from this superb food, it must be thawed properly. This is especially important because once the Mysis are fully thawed, they are not refreezable (Adib, 2004). Most hobbyists tend to simply thaw their mysids in aquarium water, which has the virtue of thawing it quickly but is not the best approach. The faster the frozen shrimp is thawed, the more likely it is to be damaged in the process. We want the mysids to remain intact and lifelike; we don’t want the tissue of the Mysis to begin to breakdown in the process of freezing/thawing. The goal is to preserve the Mysis and retain all those precious shrimp juices when we thaw it, not to release their fluids into the aquarium water where it will only degrade the water quality and do your seahorses no good!
So don’t thaw frozen Mysis in 75°F-80°F aquarium water. Don’t nuke it in the microwave to defrost it! And don’t simply toss a chunk of frozen Mysis in your tank and let it float around until it thaws and releases individual mysids!
Nor should you thaw it in tap water, distilled water, or any other source of freshwater. You want to thaw the shrimp in water that is about as salty as their own bodily fluids so there is little or no difference in osmotic pressure. Freshwater will tend to move into the mysids as they thaw and can break down their integument and rupture cell walls as they swell; excessively salty water will tend to draw water out of the Mysis as they thaw, desiccating them in the process. Normal strength seawater is just right for thawing.
So the recommended method for thawing frozen Mysis is to use refrigerated saltwater from your aquarium. Keep a small jug of your artificial saltwater in your refrigerator and reserve this for thawing your mysids (Adib, 2004). Place a couple of ounces of the chilled saltwater in a small cup or similar receptacle and use that to thaw the shrimp. Break off a small chunk from the mass of frozen Mysis — just enough for one feeding or a day’s worth at most (with experience, you will soon learn exactly how much to use) — place it in the cup of saltwater and allow the Mysis to slowly thaw in the refrigerator for 30-45 minutes (Adib, 2004). Then take the cup out of the refrigerator and allow the thawed Mysis to warm up at room temperate for another 15 minutes (Adib, 2004). This method leaves the mysids perfectly intact and lifelike, and produces immaculate shrimp that need no further rinsing. (If you use another method for thawing the Mysis, it’s generally advisable to rinse the thawed shrimp in a brine shrimp net to prevent fouling of the aquarium water.) You are now ready to fortify the Mysis with the enrichment formula of your choice.
Carefully remove the individual thawed mysids from the thawing container using a plastic fork or a toothpick and gently deposit them in the bowl of a plastic spoon. The idea is to handle the shrimp as little as possible during the thawing and enriching process, since rough handling can cause the mysids to break apart. If your enrichment product is in powder form such as Vibrance (which I recommend), take a pinch of the formula, sprinkle it on the Mysis, and mix it in very gently (a plastic knife or similar instrument works well for this step). The orange power will adhere to the moist Mysis, and when you’re done, the head region (cephalothorax) of the mysids should be stained reddish. (If your preferred supplement is a liquid formula, just add a few drops to the Mysis and let it soak in.)
With a little practice, most hobbyists quickly work out their own technique for preparing enriched Mysis. The method outlined above works well for me and many other aquarists, but there are many other ways of defrosting and enriching the Mysis that work equally well. For instance, other hobbyists prefer to add a dusting of enrichment powder (or a few drops of a liquid supplement) to a chunk of frozen Mysis and gently mix it in (or allow it to soak in) as it thaws. One nifty way to do this is to break off my little chunk of frozen shrimp and place it on a square of wax paper, allow it a while to defrost, and then add a pinch of enrichment formula and roll the Mysis and power in the wax paper as though making a cigarette. This technique is trickier and takes a little experience before you can pull it off properly. The thawing and rolling/mixing process must be done very, very carefully or you may crush some of the Mysis and lose a lot of shrimp juice while preparing it. As always, if you’re doing it right, the heads of the individual Mysis shrimp should end up stained red, which is a feeding "trigger" captive-bred chowhounds find hard to resist. With a little practice, you will soon refine your own method for preparing frozen Mysis that works the best for your schedule and the needs of your herd.
But however you prepare it, it’s important to keep the enriched Mysis refrigerated until it’s used, and to use all the Mysis you thawed and enriched within 24 hours. For best results, the enriched Mysis should be used immediately after it’s prepared. Whether it’s been refrigerated or not, avoid using thawed and prepared Mysis that is 2 or 3 days old. We don’t want to offer our seahorses food that might have become laden with bacteria.

(2) When it comes to feeding, give new arrivals time to recover and settle into their new surroundings before you force the issue.
That’s a long haul from Hawaii, and it sometimes take new arrivals a good week or two to settle in, make themselves at home, and start feeding normally afterwards. For that reason, I suggest the hobbyist have a supply of live food on hand whenever acclimating new additions to his herd. The tiny red feeder shrimp from Hawaii (Halocaridina rubra) are ideal for this, but live Gammarus, ghost shrimp, or even adult brine shrimp will do. The live shrimp help them adjust during the initial acclimation period when you first introduce your seahorses to your tank. The live foods will give the new arrivals a head start, help them recover from shipping stress quickly, and get them through the difficult period of adjustment in tiptop condition.
Don’t worry about feeding your seahorses immediately after they arrive. Give them a good 24 hours to adjust and settle down first. After the adjustment period, go ahead and offer some carefully thawed Mysis to your seahorses each day. Many seahorses handle shipping and acclimation with ease and never miss a beat, gobbling up frozen Mysis from Day One. Others will need more time before they feel at home in their new surroundings, and may not feel comfortable enough to accept frozen Mysis from their keeper until a week or two has passed. So keep offering Mysis each day, but feed it sparingly at first and remove any uneaten Mysis after an hour or so. Once the seahorses that start eating the Mysis first have had their fill, add some live feeder shrimp for the others that are lagging behind.
Many times all the seahorses resume feeding on the frozen Mysis right away and the live red feeder shrimp aren’t needed; in that case, simply keep them on hand for use as occasional treats. They last indefinitely in a clean, aerated plastic bucket at room temperature with a pinch of flake food sprinkled in sparingly a few times a week.
Be patient with the ones that seem more reluctant to resume feeding on frozen Mysis. Don’t isolate them from the others, don’t pester them by persistently trying to target feed them at this point, and don’t keep dropping frozen shrimp on their heads! That can spook a high-strung seahorse and stress him out all the more, setting him back further. Just give them time and they will soon join the others, scarfing down frozen Mysis greedily again. This can sometimes take a couple of weeks. (Mature males often lag behind at first; for some reason, they seem to be more shy and retiring than females, which can be quite brazen at times. I suspect this is due to their parental duties — during the breeding season, pair-bonded males are ordinarily ALWAYS pregnant, and they can’t risk exposing their precious cargo to any more risk than absolutely necessary.) Make a note of the reluctant eaters; the ones that are slow to take frozen Mysis now may require target feeding later on.

(3) Be aware of secretive feeders and give them plenty of room at first.
It’s quite common for new arrivals to display shy, secretive behavior. I have found that some of my seahorses, especially newly acquired specimens, are reluctant to eat while they know they are being observed. That doesn’t mean they are starving themselves, however, just that they tend to feed in secret. Rather than feeding from your hand or gobbling up the Mysis when you first offer it, they will prey upon the natural fauna in the tank, slurping up copepods and amphipods from hiding, or snatch up leftover frozen Mysis when they think no one is looking. Some of the seahorses that don’t appear to be eating at first may actually be feeding on the sly.
When that’s the case, it’s best to back off a bit and leave the tank alone as much as possible for the time being. It’s okay to observe the tank discretely but try to avoid flat-nose syndrome, and keep feeding your other specimens as usual, of course, but don’t try to force the issue with the shy ones. Just leave them be, give the seahorses plenty of peace and quiet, and let the secretive feeders adjust to their new environment and get used to the daily routine at their own speed. Before too long, they’ll begin sneaking leftover Mysis when they think you’re not watching and feel safe. Once they feel at home, the shy specimens will start exploring their tank freely and displaying themselves openly. Before you know it, they’ll come to recognize you as their feeder and begin interacting with you at dinnertime. And from there, it’s just one short step until you have them literally eating from your fingers.

(4) Morning feedings are best.
The recommended feeding regimen is to provide each of your seahorses with 4-14 frozen Mysis shrimp daily, enriched with a good food supplement, and then to fast your seahorses entirely once a week. Some hobbyist prefer to give their seahorses two feedings a day, while others prefer to give them their quota of frozen Mysis in one big meal. As long as they get their fill, there is really no right or wrong way to go about this — just do whatever works bests for your seahorses and your schedule.
However, many hobbyists find that their seahorses feed best during the morning, so if you can only feed your seahorses once a day, try to make it a morning meal. Whether it’s their biological clocks, something built into their natural circadian rhythm, or whether they’re simply hungriest shortly after waking up, seahorses do seem to feed more aggressively in the morning, and hobbyists should try to accommodate them, if possible. Breakfast, it seems, is the most important meal of the day for our aquatic equines as well as ourselves.
If you can only manage one feeding a day, DO NOT make it an evening meal. The worst thing you can do is to feed your seahorses late in the day when there will likely still be leftovers remaining at lights out. The uneaten Mysis will begin decaying overnight and put your water quality at risk. Worse still, the next morning, when they are hungriest, your seahorses may discover the bacteria-laden Mysis and snap them up off the bottom. This is an excellent way to spread disease and make your seahorses sick. Feeding your seahorses early in the day, so they have plenty of time to clean up leftovers, is a good way to prevent this. An efficient clean-up crew of scavengers also helps.

(5) Use a feeding station.
Seahorses respond very well when they are fed at the same time and place each day. They quickly learn the routine and will come to recognize their keeper as the one who feeds them — the giver of gourmet delights! Once that happens, they will often beat you to the spot, gathering around their feeding station as soon as they see you approach.
In fact, the aquarist can easily condition his seahorses to come a running at feeding time. Before you open the aquarium cover, make a point of lightly tapping it a few times or rapping on it gently. The seahorses will quickly learn to associate the tapping with the mouthwatering morsels that follow, and before you know it, they will respond by gathering at the feeding station as if you were ringing the dinner bell.
To facilitate this process and make feeding them easier, choose a feeding station that’s convenient for you in a relatively uncluttered part of the aquarium, and give your seahorses their meal right there every day. The feeding station should have some convenient hitching posts situated nearby as well. Avoid using an area where currents might whisk the food away from the seahorses before they can eat it.
I know one hobbyist who uses a toadstool leather coral as his feeding station. He places the Mysis on the bowl-shaped top of the toadstool, which contains them nicely while his seahorses perch around the edges and scarf up the shrimp as if dining at a lunch counter.
Not everyone has a toadstool coral to serve as a natural feeding station, of course, but it’s easy to make your own lunch counter that will work just as well. Get a small Pyrex bowl or a similar shallow container made of clear glass or plastic (a large petri dish works great for this) and fill it about halfway with your tank substrate (Mike Kelly, pers. com.). Then sink the bowl into your sand bed until the substrate you placed in the bowl is level with the substrate in the tank (Mike Kelly, pers. com.). Leave the rim sticking up above the sand bed about a 1/2 to 3/4 of an inch or so (Mike Kelly, pers. com.). The clear glass rim of the bowl is transparent and virtually unnoticeable, so don’t worry that it will detract from the appearance of your display tank. Artfully position a few natural hitching posts around the bowl to provide your seahorses with a handy perch from which to snick up their dinner.
At feeding time, place the frozen Mysis on the sand or gravel inside the bowl. A long tube of clear plastic 1/2′ to 1′ in diameter facilitates this. The bottom of the tube is placed in the middle of the bowl and the enriched Mysis are then placed in the top of the tube, which guides them exactly where you want them as they sink. The rim sticking above the sand bed will then keep the food in place while your seahorses dine at their leisure. Afterwards, any leftovers are neatly contained, making cleanup a breeze!
Or you can always purchase a seahorse feeding station off the shelf, ready to go, as is. Artificial cup coral makes an attractive elevated "lunch counter" that does the job nicely. Elevated on a pedestal, the seahorses can perch around the edge of the cup, which contains the frozen shrimp nicely until eaten. The coral cups are very lifelike and make nifty ready-made feeding stations if positioned at a convenient (for you and your galloping gourmets) spot in your tank where currents won’t whisk the Mysis away.
Another handy item that makes a great ready-made feeding station for seahorses are the conical worm feeders designed for offering bloodworms and tubifex worms to fish. They may require a little modifying since many of them are designed to float. Depending on the type of feeder, you may have to perforate air filled chambers around the collar, weigh it down to submerge it, or cut the conical worm trap free from the rest of the feeder. Worm feeders come with a suction cup, so once you’ve overcome the buoyancy problem, they can be secured anywhere in the aquarium you want, and they work just as well with frozen Mysis as with worms. If you position the conical feeder where a slight current hits it, gently jostling and agitating the frozen Mysis inside, it is even more effective. The flow of water imparts a bit of movement to the frozen Mysis, causing it to twitch or swirl about just a bit periodically inside the feeder. This makes the thawed Mysis look all the more lifelike and quickly attracts the interest of the seahorses. They will gather around the feeder and snick up Mysis through the open top. The conical shape of these feeders contains the frozen Mysis even better than most other feeding stations.
Some hobbyists prefer a more natural looking, aesthetically pleasing feeding station, which they fashion themselves to suit their own tastes. They start with a piece of well-cured live rock that’s approximately the right size and shape, and painstakingly hollow out the center to form a shallow concave depression. This shallow bowl is fashioned by grinding it out, using an electrical moto-tool (available at any craft store or hardware store) with a carbide burr or sometimes even a shop grinder. Once the bowl has been hollowed out, a series of holes are then drilled around the circumference of this depression. Red, brown or purple Gracilaria, green Caulerpa and/or gorgonian branches are planted in these holes to create natural hitching posts. As the macroalgae takes hold and fills out, this produces an attractive feeding station that looks completely natural. It’s a great do-it-yourself project for the handy hobbyist.
An upturned clamshell also makes a nifty natural feeding station that fits in perfectly in your seahorses’ setup. Choose a colorful natural seashell for this, such as one valve of a Tridacna clam or perhaps a Lion’s Paw Scallop shell, and you have an attractive feeding station that’s perfectly appropriate for your tank. The concave interior of the bivalve shell acts as a shallow bowl to contain the frozen Mysis until it’s eaten, and unlike some feeding stations that look out of place and detract from the appearance of your tank, a seashell looks as natural as can be in a marine aquarium. My favorite for this type of feeding station is a medium-sized Abalone shell. The iridescent, opalescent colors of the upturned interior, with its magnificent polished surface of mother-of-pearl, are spectacular! An upturned abalone shell requires no further modification whatsoever, making it the ideal feeding station for the unhandy hobbyist who’s all thumbs.
Other aquarists reserve a small, transparent glass bowl or clear plastic receptacle for feeding their seahorses. They merely place the bowl or plastic container on the bottom of the tank at feeding time, add the enriched Mysis, and let their seahorses gather round and dine at their leisure as though eating from a feeding trough. A few hours later, the feeding container is removed, along with any leftovers. Quick and easy!
For more information, see my article in Conscientious Aquarist which explains exactly how to set up a feeding station and train your seahorses to use a in greater detail.. It’s available online at the following URL:

Click here: Seahorse Feeders
<<http://www.wetwebmedia.com/ca/volume_2/cav2i5/seahorse_feeders/seahorse_feeders.htm>&gt;

(6) Target feed your seahorses and remove uneaten leftovers promptly.
The individual personalities of seahorses naturally extend to their feeding habits. Some are aggressive feeders that will boldly snatch food from your fingers, while some are shy and secretive, feeding only when they think they’re not being observed. Some like to slurp up Mysis while it’s swirling through the water column, and some will only take Mysis off the bottom of the tank. Some are voracious pigs that greedily scarf up everything in sight, and some are slow, deliberate feeders that painstakingly examine every morsel of Mysis before they accept or reject it. Some eat like horses and some eat like birds. So how does the seahorse keeper make sure all his charges are getting enough to eat at mealtime? How does the hobbyist keep the aggressive eaters from scarfing up all the mouth-watering Mysis before the slower feeders get their fair share? And how can you keep active fishes and inverts with seahorses without the faster fishes gobbling up all the goodies before the slowpoke seahorses can grab a mouthful?
Target feeding is the answer. Target feeding just means offering a single piece of Mysis to one particular seahorse, and then watching to see whether or not the ‘horse you targeted actually eats the shrimp. Feeding each of your seahorses in turn that way makes it easy to keep track of exactly how much each of your specimens is eating.
There are many different ways to target feed seahorses. Most methods involve using a long utensil of some sort to wave the Mysis temptingly in front of the chosen seahorse; once you’re sure this has attracted his interest, the Mysis is released so it drifts down enticingly right before the seahorse’s snout. Most of the time, the seahorse will snatch it up as it drifts by or snap it up as soon as it hits the bottom.
A great number of utensils work well for target feeding. I’ve seen hobbyists use everything from chopsticks to extra long tweezers and hemostats or forceps to homemade pipettes fashioned from a length of rigid plastic tubing. As for myself, I prefer handfeeding when I target feed a particular seahorse.
But no doubt the all-time favorite implement for target feeding seahorses is the old-fashioned turkey baster. The old-fashioned ones with the glass barrels work best because the seahorses can see the Mysis inside the baster all the way as it moves down the barrel and out the tip. By exerting just the right amount of pressure on the bulb, great precision is possible when target feeding with a turkey baster. By squeezing and releasing the bulb ever so slightly, a skillful target feeder can keep a piece of Mysis dancing at the very tip of the baster indefinitely, and hold the tempting morsel right in front of the seahorse’s mouth as long as necessary. Or if the seahorse rejects the Mysis the first time it drifts by, a baster makes it easy to deftly suck up the shrimp from the bottom so it can be offered to the target again. In the same way, the baster makes it a simple matter to clean any remaining leftovers after a feeding session. (You’ll quickly discover the feeding tube is also indispensable for tapping away pesky fish and invertebrates that threaten to steal the tempting tidbit before an indecisive seahorse can snatch it up. And it’s great for tapping on the cover to ringing the dinner bell and summon the diners for their gourmet feast!)
In short, target feeding allows the hobbyist to assure that each of his seahorses gets enough to eat without overfeeding or underfeeding the tank. And it makes it possible to keep seahorses in a community tank with more active fishes that would ordinarily out-compete them for food, since the aquarist can personally deliver each mouthful to the seahorses while keeping more aggressive specimens at bay.
The key to keeping active specimens like firefish or compatible clownfish or cleaner shrimp successfully with seahorses is to feed the other fish and inverts with standard, off-the-shelf aquarium foods first, and once they’ve had their fill, then target feed the seahorses.

(7) If possible, stick with frozen Mysis relicta from Canada.
Although there are several types of frozen Mysis on the market, the deep, cold water habitat and the unique way its captured and prepared makes Mysis relicta far superior to the others for feeding seahorses due to a variety of reasons (nutritional value, each individual shrimp is frozen whole and intact, the most lifelike in appearance, natural odor attractants, etc.). The fatty acid profiles of Mysis relicta are higher than that of enriched brine shrimp and it has more than three times the fatty acid content of ocean krill (Piscine Energetics. 2003). These high levels of fatty acids not only provide seahorses with essential nutrition, but also stimulate a positive feeding response (Piscine Energetics. 2003). Mysis relicta are high in protein and high in animal fat, yet are sodium free. The lack of salt intake is desirable for marine fishes, which are constantly working to expel salt from their bodies (Piscine Energetics. 2003). Suffice it to say that almost all farm-raised seahorses are pretrained to eat frozen Mysis relicta, and that’s the species they will eat the best in the hobbyist’s home aquarium as well.
One big reason for this is Mysis relicta’s highly diversified eating habits. The food chain in the deep, cold waters that this species prefers gives it extremely high levels of EPA and DHA (fatty acids), which are not only important for the nutrition they provide, but also act as natural appetite stimulants, triggering a positive feeding response in seahorses (Piscine Energetics. 2003).
Another reason Mysis relicta is eaten so greedily by seahorses is that it is virtually identical in appearance to the mysids that are a favorite food of all Syngnathids in the wild. Equally important, the Mysis relicta are flash-frozen after harvesting while they are still alive and kicking (Piscine Energetics. 2003). Their lifelike appearance is thus perfectly preserved, and they reach the consumer as whole intact shrimp. This is very important because seahorses accept frozen shrimp much more readily when the eyes and head are intact. I have observed on many occasions that when frozen Mysis are broken and fragmented, as is common with some brands, the seahorses will often eat the anterior portion with the eyes and antennae still present, and totally ignore the rest of the parts. Needless to say, that’s not only wasteful but also bad for your water quality. Mysis relicta thaws as whole, intact, individual shrimp, preventing such problems.
In short, Piscine Energetics frozen Mysis relicta has a superior nutritional profile and is a very desirable food source for large seahorses and other marine fish. But the PE frozen Mysis is by no means a prerequisite for keeping Ocean Rider seahorses. If you find the PE Mysis difficult to obtain locally, your seahorses will be quite content with another good brand of frozen Mysis that is readily available in your area. In fact, young seahorses often prefer the smaller Hikari frozen Mysis until they have grown large enough to handle the jumbo PE frozen Mysis.
I normally obtain my PE frozen Mysis from Premium Aquatics because they offer it online in small quantities, and they offer it graded for size (when they have it in stock, you can obtain either small Piscine Energetics Mysis relicta or the usual king-sized PE Mysis relicta).
If you want to go with the PE Mysis relicta, you can order it online from Premium Aquatics (see link below).

Click here: Frozen Foods: Premium Aquatics
http://www.premiumaquatics.com/Merchant2/merchant.mvc?Screen=CTGY&Category_Code=Mysis

If Premium Aquatics is out of the PE Mysis relicta, which happens at certain times of year, your next best bet is to contact Piscine Energetics and obtain a list of the retail outlets that carry their Mysis relicta. Depending on where you live, you may be able to obtain the PE Mysis relicta from a local fish store in your area:

Click here: Mysis Relicta — Natural fish food,for finicky saltwater and freshwater fish, by Piscine Energetics
http://www.mysis.com/about.html

If piscine energetics frozen Mysis relicta proves to be difficult to obtain in your area, frozen Mysis is available in several different brands from many different sources, and one of the other brands will suffice. Gamma brand frozen Mysis is good, Hikari frozen Mysis is quite acceptable as is San Francisco Bay brand frozen Mysis, the tiny Mini Mysis from H2O Life work very well for small seahorses, and Piscine Energetics frozen Mysis is, of course, perhaps the best in terms of nutritional content and quality control. Your local fish stores should carry one or more of these brands. One way or another, you need to line up a good source of frozen Mysis to serve as the staple, everyday diet for your domesticated seahorses.

(8) Observe fast days and don’t overfeed.
One of the most common mistakes hobbyists make is to overfeed their seahorses. Any excess Mysis that’s not eaten within an hour or two of a feeding can become a threat to your seahorses. Either it will find its way into some inaccessible nook of the aquarium and begin to decay, degrading your water quality, or it may be noticed by a hungry seahorses hours later or perhaps even the next day, and eaten after bacteria have gone to work on it. The best way to avoid such problems is to target feed and remove leftovers promptly, as soon as you’re sure all the seahorses have had their fill. If you can only feed once a day, make it a morning meal before you leave for work, so the seahorses have the rest of the day to glean their leftovers. A good cleanup crew can also help by taking care of any uneaten morsels that slip past the aquarist.
It’s equally important to observe the once-a-week fast day. Fasting helps prevent any potential problems with hepatic lipidosis (fatty liver disease) and keeps your seahorses feeding aggressively rather than losing interest in frozen foods. The problem is that although fasting is very healthy for seahorses on a staple diet of enriched Mysis, it can be very hard on the hobbyist. Here’s how I described this dilemma in a recent aquarium magazine article (Giwojna, Jun. 2002):
"The only thing I don’t like about this extremely nutritious diet is the obligatory fast day. The problem with fasting is that my mustangs don’t seem to realize it’s good for them — that it’s absolutely in their own best interests, essential for their long-term health. Whenever I make an appearance on fast day, they insist on parading back and forth in front of the glass in their greeting colors, begging for a handout. Before my butt hits the upholstery, both of them will be dancing at the feeding station, impatiently awaiting their gourmet shrimp dinner. When it doesn’t materialize, they forlornly abandon their post at the lunch counter, and come up to stare at me through the front glass. When I still don’t take the hint, the female paces back and forth at the front, looking her brightest and most conspicuous, as though trying to attract my attention, while the male reverts to his drab everyday attire and dejectedly resumes his futile vigil at the feeding station. If not for their well-rounded cross-sections, one would think they were dying of hunger, making it difficult to resist their puppy-dog antics. Just sitting there ignoring them makes me feel like a first-class heel. Sheesh–talk about your guilt trips…Dang! I hate fast days." (Giwojna, Jun. 2002)

There you have it, Toni — everything you need to know about feeding captive-bred-and-raised seahorses. If you follow these feeding tips, it should help keep your seahorses eating their best and you will soon find that keeping them well fed is fun and easy. Feeding time for my seahorses is always a high point in my day. They do appear amazingly like fire-breathing Dragons when they eat frozen Mysis — it looks for all the world like smoke is shooting out of their "ears" when they eat enriched Mysis, due to the pulverized particles they expel from their gills after slurping it up (Gilchrist, 2002).

So take a moment to enjoy the show when feeding your seahorses. Make sure they’re all eating well, and use this opportunity to look them over closely for wounds, injuries, or signs of disease. Seahorses are natural-born gluttons. Ordinarily, these galloping gourmets are ALWAYS hungry, so when a seahorse is off its feed, that’s often an excellent early indicator that something’s wrong. It Early detection of a potential problem can be the key to curing it, so it’s a good idea for the alert aquarist to observe his prize ponies while they put on the ol’ feed bag. Make sure they all show up for mess call, are acting normally, and have a well-rounded abdomen when they’re done eating.

Before I sign off, I would also like to emphasize one more point regarding feeding frozen foods. Whether it is a tank with lots of live rock, a modified minireef, a seagrass system or a mangrove biotype, a well-designed seahorse setup is an elaborate environment. A certain level of complexity is necessary in order to assure that our seahorses behave naturally (Topps, 1999) and to provide our ponies with plenty of hitching posts and shelter, and enough sight barriers to assure them a little privacy when they feel the need to be alone. Their homemade habitat may thus take the form of a labyrinth of live rock, an intricate arrangement of corals and gorgonians, a well-planted bed of seagrass or macroalgae, or a full-fledged reef face. When feeding seahorses in such intricate surroundings, the worst thing you can do is to scatter a handful of frozen Mysis throughout the tank to be dispersed by the currents and hope that the hungry horses can track it all down. Inevitably some of the frozen food will be swept away and lodge in isolated nooks and crannies where the seahorses cannot get it. There it will begin to decompose and impair your water quality, which is why ammonia spikes are common after a heavy feeding. Or it may be wafted out into the open again later on and eaten after it has gone bad. Either outcome can lead to dire problems. Target feeding the seahorses or hand feeding them or training them to use a feeding station are the best ways to avoid such complications.

In summation, Toni, I would try your Hippocampus reidi on some of the small Hikari frozen Mysis or the Mini Mysis from H2O Life, or offer them some soft-bodied live adult brine shrimp, to see if that makes a difference and they are able to eat them without difficulty. If they can’t handle the softbodied brine shrimp or the tiny frozen Mysis either, then it’s time to consider treating for protozoans and ectoparasites that may be contributing to this problem.

Best of luck resolving these feeding issues, Toni!

Respectfully,
Pete Giwojna

Dear Toni:

There really isn’t a conclusive way for the home hobbyist to determine whether a problem with weak snick or any of the related feeding disorders is due to ectoparasites that invade the gills, perhaps aggravated by secondary bacterial infections that affect the suctorial feeding mechanism, or not. If the weak snick is accompanied by respiratory distress (e.g., huffing, rapid respirations, labored breathing) that’s a good indication that protozoan parasites could be involved, and if more than one seahorse seems to be affected, that it is often a sensible problem to treat the tank for a potential parasite problem.

There are number of ways this can be accomplished such as administering hyposalinity at a certain level and/or treating the main tank with antiparasitics in conjunction with therapeutic dips, but the appropriate treatment method depends on whether or not there are any sensitive invertebrates in the aquarium that might be harmed by antiparasitic medications or fare poorly at reduced salinity.

If you can give me a rundown of all the specimens in your seahorse tank and the current water quality parameters for the aquarium, I will be happy to help you determine the best treatment option for your case, Toni. Please get back to me with a list of all of the fish and invertebrates in your seahorse tank and we can go from there.

Respectfully,
Pete Giwojna

Dear Toni:

I’m very sorry to hear that you lost the orange female to this problem. Your water quality parameters are fine, so I don’t believe that your water chemistry is at fault or contributed to the problem with weak snick or the demise of the female Hippocampus reidi. It’s good to see that the yellow H. reidi are still doing well but we need to shift our attention to saving the orange male at this point.

Unfortunately, because of all of the sensitive invertebrates in your seahorse tank, we are severely limited in our options for treating your main tank for a possible problem with protozoan parasites, Toni. None of the anti-parasitic medications can be used safely in an aquarium that houses starfish, cleaner shrimp, and live corals and gorgonia. The best we can do under the circumstances would be to administer a modified form of hyposalinity at a specific gravity that is safe for reef tanks (i.e., ~1.017) in order to control protozoan parasites in the main tank while you transfer the orange male to a hospital tank so that he can be treated for his weak snick using the appropriate medications. I will provide you with instructions for administering hyposalinity in your main tank safely later in this post, but first let’s discuss how best to treat the orange male.

I recommend treating the orange male in your hospital tank using either Parinox or else combination of acriflavine and Furan2, whichever is easier for you to obtain.

Parinox is an anti-parasitic medication from National Fish Pharmaceuticals (www.fishyfarmacy.com) that is an effective protozoacide and also has antibacterial properties. This makes it effective for treating some cases of weak snick in which protozoan parasites and secondary bacterial infections may be preventing the seahorse from feeding properly, but it would be very destructive for the invertebrates in your seahorse tank, so it should only be administered in a hospital tank, as discussed below, Toni:

Parinox

USE: for ich, Hexamita, costia, ichthyophthirius, ectoparasites, monogenia (trematodes), Hirudinea, parasitic copepods, argulus, Lernaeidae, anchor worms, fish lice, leeches. Also a protozoacide. Antibacterial, antiparasitic — very wide spectrum. Our version of a "cure-all."

DOSAGE: 1/4 teaspoon per 20 gallons of water. Treat once a week for two weeks. If water changes are done, add back the percentage of the medication according to how much of the water was changed.

However, Parinox is not available from local fish stores or pet shops, so you would have to order it online from National Fish Pharmaceuticals. For this reason, you may be better off treating your orange male H. reidi using acriflavine together with Furan2, providing you can obtain both of these medications locally and avoid any further delay in treatment.

When used together, those two medications (acriflavine + Furan2) are also very effective in treating weak snick when it is due to protozoan parasites that attack the gills and may lead to secondary bacterial or fungal infections that further disrupt the seahorse’s suctorial feeding mechanism. The acriflavine is useful in treating skin parasites and the protozoan parasites that cause marine ich (Cryptocaryon) and marine velvet (Oodinium), as well as bacterial infections such as fin rot in tail rot or fungal infections such as Saprolegnia or mouth fungus.

The Acriflavine therefore makes a very effective 1-2 punch when combined with the Furan2, which is a broad-spectrum antibiotic that is very good for combating secondary infections.

Furan2 is a good combo medication that consist of two nitrofuran antibiotics (nitrofurazone and furazolidone) plus good old methylene blue. That gives it both bacteriostatic and bactericidal properties, and makes it active against various gram-negative and gram-positive bacteria. Best of all, it can be safely combined with Aquarium Pharmaceuticals antiparasitic medications such as Acriflavine to increase its effectiveness and guard against secondary infections when you are treating for parasites.

Thus, when combined with a good antiparasitic medication like Acriflavine, a good combination drug like Furan2 can be the ultimate weapon in your medicine cabinet. It is effective against a wide range of diseases, and is very useful whenever you suspect an infection is at work, but don’t know whether you’re dealing with fungus, bacteria, protozoan parasites or a mixed infection.

However, Toni, you have to take special precautions when administering acriflavine or nitrofuran antibiotics such as this because they are photosensitive and can be deactivated by light. That means you’ll need to darken the hospital tank while you treat the seahorse(s). Do not use a light on your hospital tank and keep the treatment tank darkened throughout the treatment period.

You should also be aware that Furan2 will cause discoloration of the aquarium water, turning it a shade of blue-green. This is harmless and can be removed after the treatments using activated carbon filtration. The bluish green coloration is due to the methylene blue component of the Furan2, which thus helps to protect the other medications from light in addition to providing other benefits, as discussed below.

Commonly known as "meth blue" or simply "blue," methylene blue is a wonderful medication for reversing the toxic effects of ammonia and nitrite poisoning (commonly known as "new tank syndrome"). Since hospital tanks are usually without biological filtration, and ammonia and nitrite can thus build up rapidly (especially if you are not doing water changes during the treatment period), it’s a good idea to add methylene blue to your hospital ward when treating sick fish.

Methylene blue also transports oxygen and aids breathing. It facilitates oxygen transport, helping fish breathe more easily by converting methemoglobin to hemoglobin — the normal oxygen carrying component of fish blood, thus allowing more oxygen to be carried through the bloodstream. This makes it very useful for treating gill infections, low oxygen levels, or anytime your seahorses are breathing rapidly and experiencing respiratory distress. It is the drug of choice for treating hypoxic emergencies of any kind with your fish.

In addition, methylene blue treats fungus and some bacteria and protozoans. Methylene blue is effective in preventing fungal infections, and it has antiprotozoal and antibacterial properties as well, by virtue of its ability to bind with cytoplasmic structures within the cell and interfere with oxidation-reduction processes.

Furan2 will impair beneficial nitrifying bacteria and disrupt your biological filtration, so it should be administered in a hospital tank.

If you can find a local fish store that carries Aquarium Pharmaceutical medications or Fishvet medications, they will have both the Furan2 and the acriflavine in a form that can be combined safely together. If they have Aquarium Pharmaceutical products, they will be labeled simply Furan2 and Acriflavine respectively; if they carry Fishvet products, the appropriate medications will be labeled FuraMS and AcriflavineMS or AcroMS, and both those combinations are safe to use together in your hospital tank.

While you’re treating the orange male in your hospital tank, Toni, you should also be treating your main tank with a modified form of hyposalinity at a specific gravity of 1.017 that is safe for most corals and invertebrates.

Here are the instructions for administering hyposalinity safely in your hospital tank. The hyposalinity doesn’t require any sort of medication and is effective in controlling most protozoan parasites, as well as providing some additional benefits for the ailing seahorses. It will make it easier for your seahorses to osmoregulate and increase the dissolved oxygen in the water, which will help the seahorses to breathe and can be crucial for seahorses that may have gill parasites. Pay special attention to the section on "Modified OST for Reef Tanks," which is what you’ll be using due to the sensitive corals or invertebrates in your seahorse tank:

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Hyposalinity or Osmotic Shock Therapy (OST)

Fortunately, when problems with protozoan parasites and ectoparasites crop up, we needn’t determine which particular parasite is plaguing our seahorses, since hyposalinity or Osmotic Shock Therapy (OST) is a very safe treatment that is effective against protozoans and ectoparasites in general, with the exception of Uronema. OST is totally noninvasive and harmless to seahorses and most other fishes, can be administered safely in the display tank rather than a hospital tank to eradicate the protozoan parasites from your system, and is completely compatible with UV, ozone, and any medications you may be using (Giwojna, Dec. 2003). OST is therefore the treatment I recommend for problems with external parasites other than Uronema.

Hyposalinity also helps parasite-ridden fish avoid dehydration and save their strength by reducing osmotic pressure and making it easier for them to osmoregulate. Allow me to explain.

Because the seawater they live in is far saltier than their blood and internal body fluids (Kollman, 1998), marine fish are constantly losing water by diffusion through their gills and the surface of their skin, as well as in their urine (Kollman, 1998). The mucus layer or slime coat of the fish helps waterproof the skin and reduces the amount of water that can diffuse through its surface (Kollman, 1998). However, when the skin is attacked by parasites such as Costia, Cryptocaryon, Cryptobia, Amyloodinium, Brooklynella, Epistylus and the like, this protective barrier is damaged and water is lost at an increasing rate (Kollman, 1998). The affected fish can easily become dehydrated as a result, further debilitating them.

Low salinity is an excellent way to treat most such skin infections, since reducing the salinity helps the fish recover in several different ways. It lessens the risk of dehydration by decreasing osmotic pressure (Kollman, 1998), and reduces the amount of energy the fish must expend on osmoregulation, helping the weakened fish to recover (Kollman, 1998).

And if the salinity is dropped far enough, it prevents reinfection and provides the fish with immediate relief by destroying the parasites in the water and on the surface of the skin (Kollman, 1998). At low salinity, water moves into the parasites’ bodies by passive diffusion until they literally burst (lyse). This method of treatment is known as hyposalinity or Osmotic Shock Therapy.

At the first sign of parasitic infection, I therefore suggest instituting a two-pronged treatment regimen immediately: (1) first, administer a freshwater dip to your seahorses to reduce the number of embedded parasites, clear the gills and snout as much as possible, and provide the seahorses with some quick relief, and (2) treat your main tank with osmotic shock therapy, dropping the salinity to 15 ppt (1.011-1.012) for several weeks to eliminate the parasites from your system entirely (Giwojna, Dec. 2003). If your seahorses seem too weak to handle the stress of a freshwater dip, then just get them into hyposalinity water ASAP — no acclimation!

Step 1: Freshwater Dip

A freshwater dip is simply immersing your seahorse in pure, detoxified freshwater that’s been preadjusted to the same temp and pH as the water the seahorse is accustomed to, for a period of at least 10 minutes (Giwojna, Dec. 2003). It doesn’t harm them — seahorses typically tolerate freshwater dips exceptionally well and a 10-minute dip should be perfectly safe. Freshwater dips are effective because marine fish tolerate the immersion in freshwater far better than the external parasites they play host to; the change in osmotic pressure kills or incapacitates such microorganisms within 7-8 minutes (Giwojna, Dec. 2003). A minimum dip, if the fish seems to be doing fine, is therefore 8 minutes. Include some sort of hitching post in the dipping container and shoot for the full 10 minutes with your seahorses (Giwojna, Dec. 2003).

If you will be using tap water for the freshwater dip, be sure to dechlorinate it beforehand. This can be accomplished usually one of the commercial dechlorinators, which typically include sodium thiosulfate and perhaps a chloramine remover as well, or by aerating the tap water for at least 24 hours to dissipate the chlorine (Giwojna, Dec. 2003).

If you dechlorinate the dip water with a sodium thiosulfate product, be sure to use an airstone to aerate it for at least one hour before administering the dip. This is because the sodium thiosulfate depletes the water of oxygen and the dip water must therefore be oxygenated before its suitable for your seahorse(s). Regardless of how you detoxify the freshwater for the dip, it’s important to aerate the water in the dipping container well beforehand to increase the level of dissolved oxygen in the water. Many hobbyists leave the airstone in the dipping container throughout the procedure.

Adjusting the pH of the water in the dipping container so that it matches the pH of the water in the aquarium is a crucial step. Ordinary baking soda (sodium bicarbonate) will suffice for raising the pH of the water. If there is too much of a difference in the pH, there is a possibility the seahorse could go into shock during the dipping procedure. Preadjusting the pH will prevent that from happening. If you will are unsure about your ability to accurately adjust the pH in the dipping container, avoid this procedure altogether or be prepared to monitor the seahorse very carefully or shorten the duration of the tip to no more than about 4 minutes.

Observe the horse closely during the dip. You may see some immediate signs of distress or shock. Sometimes the horse will immediately lie on its side on the bottom. That’s a fairly common reaction — normal and to be expected, rather than a cause for concern, so don’t be alarmed if this happens. Just nudge or tap the seahorse gently with your finger if it lies down on its side. Normally, the seahorse will respond to the slight nudge by righting itself again and calm down for the duration of the dip. However, if it does not respond, stop the treatment.

Most seahorses tolerate the treatment well and experience no problems, but if you see continued signs of distress — twitching, thrashing around etc. — stop the treatment.

After you have completed the dip and returned the seahorses to the aquarium, save the dip water and examine it closely for any sign of parasites. The change in osmotic pressure from saltwater to freshwater will cause ectoparasites to lyse (i.e., swell and burst) or drop off their host after 7-10 minutes, and they will be left behind in the dipping water. Protozoan parasites are microscopic and won’t be visible to the naked eye, but some of the other ectoparasites can be clearly seen. For example, monogenetic trematodes will appear as opaque sesame seeds drifting in the water (Giwojna, Aug. 2003) and nematodes may be visible as tiny hairlike worms 1/16-3/16 of an inch long. Other parasites may appear as tiny dots in the water. Freshwater dips can thus often provide affected seahorses with some immediate relief by ridding them of these irritating pests and can also aid their breathing by flushing out gill parasites.

It’s best not to dip all of the seahorses simultaneously. I would dip them individually so you can keep a close eye on each seahorse throughout the dip and make sure it is tolerating it well. That way, you can use the same dipping container and dipping water for all for seahorses as you dip them in sequence. I like at least a gallon of water in the dipping container, but that depends on what I’m using. If it’s a clean three or five-gallon bucket, I will fill it about half full with freshwater adjusted to the aquarium temperature.

Step 2: Hyposalinity (Osmotic Shock Therapy)

Osmotic Shock Therapy (OST) involves maintaining the saltwater in your system at a much lower specific gravity than normal: 1.017 is recommended for reef tanks with live coral and invertebrates, while 1.011 (15 ppt salinity) is appropriate for fish-only tanks (Giwojna, Dec. 2003). Essentially, OST simply places the infectious organisms in an environment in which they cannot hope to survive while the host (or infected fish) is unaffected (Hauter, 2004). It is therefore the parasites that are subjected to the shock, not the fishes, which are normally quite content at the prescribed salinities (Giwojna, Dec. 2003). This low salinity method can be thought of as a continuous freshwater dip, and provides basically the same benefits as a 5-10 minute freshwater dip does, only long term (Giwojna, Dec. 2003).

When the salinity in the system is lowered initially, it is done as if performing a normal water change, except that the replacement water is simply treated tap or RO water without the salt (Don Carner, pers. com.). (If the replacement water is RO/DI or other softened source, then a buffering agent should be employed to prevent pH and alkalinity drops; Thiel, 2003.) Make sure the freshwater you add is thoroughly mixed with the remaining saltwater in the tank as you proceed. This will assure that your salinity/specific gravity readings are accurate. Monitor the lowering closely so as to not reduce it too fast. Achieving the desired specific gravity (1.010-1.012) over a period of several hours is fine (Don Carner, pers. com.). The bacteria colony in the biofilter will survive, the fish will survive, but the parasites will not (Don Carner, pers. com.).

By lowering the salinity, we are also lowering the osmotic pressure of the water. The parasites NEED high osmotic pressure externally in order to maintain a normal water balance within their bodies (Don Carner, pers. com.). Reduce the salinity of the surrounding saltwater sufficiently, and water moves via osmosis into the parasites’ bodies until they literally explode (Giwojna, Dec. 2003). As a higher life form, the fish can withstand this treatment very well; invertebrates and parasites cannot (Don Carner, pers. com.).

For best results, I recommend removing your seahorses to a hospital tank or bucket filled with full strength saltwater (1.022-1.025) while dropping the salinity in the main tank. They can be given their freshwater dips while you are reducing the salinity in the main tank. Once the specific gravity in the display tank has been lowered to the desired level, the seahorses can then be released directly into the main tank without any acclimation whatsoever. They will make the transition from full strength saltwater to hyposalinity wonderful well, without missing a beat, whereas the ectoparasites they are carrying will be subjected to a lethal change in osmotic pressure.

Do not hesitate to maintain the hyposalinity for the entire treatment period. OST needs to maintained for at least 3 weeks in order to assure that all of the encysted parasites have reached the free-swimming stage of their life cycle and been killed. For best results, the hyposalinity should be maintained for 6-8 weeks to assure that all of the parasites have been destroyed.

CAUTION! When administering hyposalinity to seahorses, be very careful as you add the freshwater when you approach the target salinity. You do NOT want to overshoot the mark and drop the salinity too far! Seahorses tolerate low salinity very well up to a certain point, but they cannot withstand salinities below 13.3 ppt (specific gravity = 1.010) indefinitely. Salinities below 1.010 may be fatal to seahorses in a matter of days, if not hours.

In the olden days, many attempts were made to gradually convert seahorses from saltwater to freshwater. Hippocampus erectus tolerated these experiments splendidly all the way down to specific gravity of 1.010, but when the salinity was dropped any further, the seahorses all perished (Bellomy, 1969, p7). These experiments were repeated with several groups of seahorses representing different subspecies of erectus, and the results were always the same: fine as low as 1.010 — defunct at 1.009 (Bellomy, 1969, p7)!

Keeping that in mind, it is best to make your target salinity 1.011-1.012 to allow a margin for error, and to transfer your seahorses to a hospital tank while you drop the salinity in the main tank. That way no harm will be done if you accidentally take the salinity down too far in your main tank before readjusting it and hitting your target salinity. And when you return the seahorses from normal salinity in the hospital tank to the main tank at 1.011-1.012, the parasites will be subjected to the greatest possible osmotic shock, leaving them no chance at all to adjust to change in osmotic pressure.

To be safe and effective, administering hyposalinity requires the use of an accurate method for measuring salinity/specific gravity such as a refractometer. If you will be relying on a pet-store hydrometer for your readings, you may wish to consider alternate treatments rather than OST. If you do decide to try hyposalinity using a hydrometer, please observe the following precautions:

Be aware of the temperature at which your hydrometer was calibrated and make full use of conversion charts to adjust your readings based on the actual temperature of the water aquarium water.

Make your target salinity 20 ppt (specific gravity = 1.015) to allow for a greater margin for error.

In addition, when administering OST it is important to monitor your ammonia and nitrite levels closely at first. Hyposalinity may temporarily impact the nitrifying bacteria in your biofilter, so check your readings closely to see if there is a spike once you’ve reached your target salinity. If so, a simple water change will correct the problem and your biofiltration will be back to normal shortly.

The hobbyist should also bear in mind that hyposalinity can delay gonadal development in immature seahorses and may also prevent mature seahorses from breeding until the salinity is returned to normal. So don’t maintain low salinity for the long term — as soon as the 3-4 week treatment period is over, bring the specific gravity in the main tank back up 1.024-1.025.

When you are ready to return the system to normal salinity, simply reverse the process, remove some of the low salinity water in the aquarium and replace it with high salinity water. Take your time and raise the salinity slowly and gradually. Fish can become dehydrated if the salinity is increased too rapidly, so be methodical and raise the salinity over a period of several days. Don’t hesitate to take a full week to return the specific gravity to normal levels again in small increments.

If your tank contains corals or delicate invertebrates, or you just want to be extra cautious with your seahorses as they recuperate, adjust the salinity more slowly. This can be accomplished by making smaller water changes, which will require more steps to raise the salinity back to normal, or by reducing the specific gravity of the high-salinity replacement water somewhat. Make the adjustment back to normal salinity as gradually as necessary in order to be confident that you are not stressing the specimens. The hyposalinity should already have done its job so you can afford to be cautious when readjusting the salinity. Take all the time you want.

To be absolutely certain that things go smoothly, take advantage of the online Salinity Adjustment Calculator at the following web site: http://saltyzoo.com/SaltyCalcs/SalinityAdjust.php

This calculator takes the amount of water in your system, your current salinity, the salinity you’d like to achieve, and the maximum change in salinity that you are willing to risk per water change into consideration and performs the necessary calculations. It then returns the number of gallons and salinity of the water for each change (Taylor, 2001b).

The low salinity system was initially developed at the Instant Ocean Hatcheries in the 1980’s and has since been perfected by other large-scale operations (Giwojna, Dec. 2003). Thomas Frakes at Aquarium Systems recommends this system and Rand Kollman recently conducted a controlled study of the method, as described below (Kollman, 1998):

During the study, fourteen 40-gallon tanks connected to a common filtration system at Kollman’s dealership were run at 15 ppt salinity (specific gravity = 1.011), while sixteen other 30-gallon tanks, connected to their own separate filtration system, were maintained at normal salinities of 27-30 ppt (specific gravity = 1.020-1.022) and served as the control group for the experiment (Kollman, 1998; Giwojna, Dec. 2003). Both systems had identical filtration and were maintained at the same temperature (between 79-80 degrees F), Kollman, 1998.

The test period ran continuously from 1994 to 1997, during which time marine fish from the Red Sea, Caribbean and throughout the Indo-Pacific were maintained in both systems (Kollman, 1998). Whenever fish arrived from wholesalers or transshipments, they were divided evenly between the low salinity and the normal salinity (control) system with no acclimation procedures whatsoever (Kollman, 1998; Giwojna, Dec. 2003). No differences in behavior were observed between the fishes in the two systems during the trial period (Giwojna, Dec. 2003).

The results of the three-year study were dramatic and conclusive (Giwojna, Dec. 2003). Outbreaks of Amyloodinium, Cryptocaryon, turbellarians, and monogenetic trematodes were simply not seen in the low salinity system, and periodic microscopic examinations of skin scrapings and gill clippings confirmed that none of the parasites were present (Kollman, 1998; Giwojna, Dec. 2003). On the other hand, the normal salinity control system continued to have periodic outbreaks of all the above parasites. Furthermore, infected fish from the control system were cleared of their parasites within a few days if transferred to the low salinity system (Kollman, 1998; Giwojna, Dec. 2003).

Kollman found the low salinity system reduced his previously high mortality rates and that his dealership was able to greatly reduce chemical treatments and subsequent overdoses (Kollman, 1998; Giwojna, Dec. 2003). He concluded that a salinity of 14 to 15 ppt (specific gravity = 1.010-1.011) was an effective treatment level to which fish can be immediately transferred with no special acclimation procedures (Kollman, 1998; Giwojna, Dec. 2003). Although the rapid turnover of specimens at his dealership prevented him from reaching any definitive conclusions about the long-term effects of low salinity on marine fishes, Kollman noted that several fish were maintained in the system for well over a year with no ill effects, and that a Red Sea angelfish (Pomacanthus maculosus) thrived in the low salinity system for three-and-a-half years (Kollman, 1998; Giwojna, Dec. 2003)!

Kollman’s study and the ongoing program at Instant Ocean hatcheries are not the only reports on utilizing low salinity water to quarantine specimens held under crowded conditions (Giwojna, Dec. 2003). As early as 1985, Colorni published a study in Diseases of Aquatic Organism on the effectiveness of hyposalinity in controlling Cryptocaryon irritans in cultured sea bream (Colorni, 1985). Randolph Goodlett and Lance Ichinotsubo have likewise reported their own low-salinity treatment techniques, recommending at least 3 weeks exposure at 14 ppt (specific gravity = 1.010) for a broad range of marine tropical fish species to control various parasites (Goodlett and Ichinotsubo, 1997). They too reported that fish handled immediate transfer into low salinity water "beautifully (Goodlett and Ichinotsubo, 1997)." Variations of low salinity or OST are also gaining popularity among reefkeepers for curing disease outbreaks in reef tanks where copper and other medications cannot be used (Frakes, 1994; Giwojna, Dec. 2003).

Low Salinity Pros (Giwojna, Dec. 2003):

1. Less stressful and longer lasting than freshwater dipping.
2. More effective than freshwater dipping outside the aquaria, since OST kills the free swimming parasites as they emerge from dormant cysts/spores within the aquaria/system as well as those attached to the fish (i.e., the fish are not reinfected once they are returned from the bath to the main tank).
3. No special acclimation procedures required for newcomers.
4. Suitable for all marine teleost (bony) fishes (Red Sea, Indo-Pacific, Florida & Caribbean).
5. Seahorses tolerate hyposalinity extremely well.
6. Eliminates outbreaks of Cryptocaryon irritans (White Spot Disease/Marine Ick).
7. Eliminates turbellarians (Black Spot/Clownfish Disease).
8. Eliminates most ectoparasites, including trematodes, flukes, leeches and Argulus;
9. Prevents the spread of protozoal parasites in general.
10. Reduces the risk of dehydration when the integrity of the fish’ slime coat is disrupted;
11. Helps weakened fish conserve energy and husband their strength by lowering osmotic pressure and making it easier for them to osmoregulate.
12. Reduces dependency on chemical treatments such as copper and formalin.
13. Eliminates the risk of overdoses.
14. Proven to improve the health of marine teleost fishes kept in crowded containment systems with a heavy biological load.
15. Can be used safely with protein, skimmers, ozone, UV, and other treatments.
16. Increases the levels of dissolved oxygen in the aquarium, making it easier to breathe.
17. Helps prevent gas supersaturation, minimizing problems with gas bubble syndrome.

Low Salinity Cons (Giwojna, Dec. 2003):

1. Sharks and rays are unable to adjust to low salinity systems or tolerate OST.
2. Cannot be used with corals and invertebrates at salinities recommended for fishes.
3. Can be harmful to seahorses at salinities below 13.3 ppt (specific gravity = 1.010).
4. May delay gonadal development in seahorses and prevent breeding until the salinity is returned to normal.
5. Requires an accurate method for measuring salinity/specific gravity such as a refractometer for best results.
6. May not be helpful in cases of Uronema — the most common protozoan parasite infection in seahorses.
7. May impact nitrifying bacteria in the biofilter temporarily.
8. Not recommended for long-term maintenance (this will not be a concern for any fishes that are in the system for 6-8 weeks or less).
9. Results vary — many hobbyists report great success with hyposalinity; others have no luck using this technique. Much depends on how OST was administered, how low the salinity was reduced and how quickly it was dropped, the accuracy of the salinity measurements, the particular parasite(s) involved and how early treatment was begun.

Invertebrates differ in their tolerance for hyposalinity. Kollman notes that he was able to keep several crustaceans at a fairly low salinity of 18-19 ppt (specific gravity = 1.013 to 1.014). These included arrow crabs, peppermint shrimp, and emerald crabs (Kollman, 1998). Hermit crabs are generally perfectly happy undergoing OST, echinoderms (starfish and urchins) typically don’t tolerate it at all, most shrimp are sensitive, snails vary (Giwojna, Dec. 2003). Nerites and periwinkles don’t mind it at all, others are okay at 1.017 but you can kiss them goodbye at 1.010. Most corals are vulnerable to full OST (Giwojna, Dec. 2003). Reefkeepers and hobbyists with sensitive animals usually do a modified version of OST where they lower the salinity to 1.017 rather than 1.010 (Giwojna, Dec. 2003). The delicate animals generally tolerate 1.017 well and although that’s not as effective in eradicating parasites, a specific gravity of 1.017 is still low enough to provide many of the benefits of hyposalinity (Giwojna, Dec. 2003).

For a standard SHOWLR setup with a clean-up consisting of assorted snails, microhermits, and cleaner shrimp, I recommend relocating the snails and shrimp while treating your seahorse system with full OST at a specific 1.011-1.012 for several weeks. If that’s not practical because it would be too difficult to account for all the snails and/or shrimp and remove them, then I would suggest taking the salinity carefully down to about 1.017 in your main tank, which most of your janitors should tolerate just fine, after moving your seahorses to your hospital tank for treatment at full OST.

Just set up your hospital tank at a salinity of 15-16 ppt (a specific gravity of 1.011-1.012) and adjust the water to the same temp and pH as the main tank. Then administer a freshwater dip to your seahorses, and transfer them directly into the hyposalinity treatment tank afterwards without any acclimation whatsoever.

As I mentioned earlier, OST is completely compatible with most medications. (In fact, many medications are more effective at low salinity than they are in full strength saltwater.) Since secondary bacterial or fungal infections often accompany parasite problems, I would also recommend combining hyposalinity in the hospital tank with antibiotic therapy. In that case, simply medicating the hospital tank with the appropriate antibiotics will be easier than administering the antibiotics orally via gut-loaded shrimp. [CAUTION: if administering hyposalinity in your main tank, do not administer antibiotics, which may adversely impact the biofiltration in the aquarium.]

Nifurpirinol used in conjunction with neomycin will be very effective for medicating the hospital tank during OST, as will the powerful combination drugs that contain both antiprotozoal and wide-spectrum antibacterial agents. Look for a product that includes ingredients such as nitrofurazone and metronidazole, which are very effective against protozoan parasites, as well as antibiotics such as neomycin and kanamycin, which are powerful broad-spectrum medications.

Modified OST for Reef Tanks

Reefers generally run a modified version of OST in which they maintain a somewhat higher specific gravity, usually around 1.017 (Thiel, 2003), for a longer period of time in order to control protozoal parasites. Most corals are safe at even lower salinities, but 1.017 usually provides adequate protection and provides a margin for error. In any case, as a rule, reef keepers DO NOT take their systems lower than 1.015 for safety’s sake (Thiel, 2003). (This is also a good option for hobbyists who have only a typical pet-store hydrometer for measuring specific gravity, or anyone with many invertebrates in their seahorse setup.)

Corals typically close slightly immediately after the salinity is lowered, but are open fully again by the next day, and suffer no harmful long-term effects from hyposalinity at 1.017 whatsoever (Thiel, 2003). Reefers who practice OST report that it has no long-term detrimental effects on the growth rate of their corals.

According to Thiel, corals that are know to be sensitive to hyposalinity, and which are thus not well suited for OST, include Seriotopora hystrix, Montipora digitata, Pocillopora species and other similar hard corals with a fine, dense, polyp structure (Thiel, 2003). Acropora species, however, handle hyposalinity well and soft corals are also generally fine, including such sensitive softies as Xenia, Lemnalia, and the like (Thiel, 2003). As long as the pH and alkalinity are maintained at normal levels, most hard corals are not harmed at a specific gravity as low as 1.017.

Don’t return any sensitive invertebrates to the main tank until the entire regimen of hyposalinity has been completed and the aquarium has been returned to normal salinity again.
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Okay, Toni, that’s the lowdown on hyposalinity. While the orange male is being treated in your hospital tank, you can go ahead and administer hyposalinity to the main tank at a specific gravity of 1.017 in order to control any protozoan parasites it may be harboring. This should help prevent the orange male from being reinfected once he is returned to your main tank, and will help protect your yellow reidi so that they aren’t affected and continue to eat well.

Best of luck resolving your seahorses’ feeding difficulties and getting your seahorse tank back on track, Toni.

Respectfully,
Pete Giwojna

Dear Toni:

You can send the picture of your ailing seahorse to me at the following e-mail address anytime: [email protected]

I will keep an eye out for it and sent you a reply as soon as I have had a chance to examine the photo.

Good luck!

Respectfully,
Pete Giwojna