You may want to consider treating your seahorse with a regimen of metronidazole, sir.
I am thinking that metronidazole may be helpful in your case because it is often used to treat seahorses that are losing weight despite eating well or that have lost their appetite and stopped eating, since an increasing population of intestinal flagellates in the gut of the fish is a common cause for the loss of appetite, and the metronidazole is very effective in eliminating the flagellates, Michael, as explained below in more detail:
Intestinal flagellates are microscopic organisms that move by propelling themselves with long tail-like flagella (Kaptur, 2004). Such flagellates can be found naturally in both the gastrointestinal and reproductive tracts of their hosts. In low numbers they do not present a problem, but they multiply by binary fission, an efficient means of mass infestation when conditions favor them (such as when a seahorse has been weakened by chronic stress), Kaptur, 2004. When they get out of control, these parasites interfere with the seahorse’s normal digestive processes such as vitamin absorption, and it has difficulty obtaining adequate nourishment even though it may be eating well and feeding heavily (Kaptur, 2004). Suspect intestinal parasites are a work when a good eater gradually wastes away despite its hearty appetite (Giwojna, Dec. 2003). Their presence can be confirmed by examining a fecal sample under a microscope, but they can be easily diagnosed according to the more readily observed signs described below (Kaptur, 2004).
The symptoms to look for are a seahorse that’s losing weight or not holding its own weightwise even though it feeds well, or alternatively, a lack of appetite accompanied by white stringy feces (Kaptur, 2004) or mucoid feces. Many times the vent or abdomen of the affected fish is swollen. When a seahorse stops eating aggressively and begins producing white, stringy feces or mucoid feces instead of fecal pellets, that’s a clear indication that it’s suffering from intestinal flagellates (Kaptur, 2004). Treat the affected seahorse(s) with metronidazole at the first sign of either condition (Giwojna, Dec. 2003).
Metronidazole is an antibiotic with antiprotozoal properties that is very effective in eradicating internal parasites in general and intestinal flagellates in particular (Kaptur, 2004). It is ideal for this because it is rapidly absorbed from the GI tract, has anti-inflammatory effects in the bowel, and was designed specifically to treat protozoal infections and anaerobic bacterial infections by disrupting their DNA (Kaptur, 2004).
If the seahorse is still eating, administering the metronidazole orally is often extremely effective (Giwojna, Dec. 2003).
If the affected seahorse is no longer eating, then it should be treated in a hospital tank or the entire aquarium can be treated (no carbon filtration, UV, or protein skimming during the treatments). Since metronidazole is only active against anaerobic bacteria, it will not affect beneficial Nitrosomonas and Nitrobacter species or disrupt the biological filtration, and it can therefore be used safely to treat the main tank (Kaptur, 2004). Dissolve 250 mg of metronidazole for every 10 gallons of water in the treatment tank, and the medication will be absorbed through the seahorse’s gills (Kaptur, 2004). Metronidazole is oxidized over a period of several hours, so the entire dose needs to be replenished daily; (Kaptur, 2004.) Treat the affected seahorse in isolation for a minimum of 5 consecutive days, or you can treat the main tank with the metronidazole providing it does not house any sensitive invertebrates.
When administered properly, metronidazole is wonderfully effective at eliminating intestinal parasites, and there should be signs of improvement within 3 days of treatment (Kaptur, 2004). The seahorse’s appetite should pick up, and as it does, those characteristic white stringy feces will return to normal (Giwojna, Dec. 2003).
Intestinal parasites are typically transferred from their host to uninfected fishes by fecal exposure, and good tank management and hygiene can therefore go a long way towards limiting their spread (Giwojna, Dec. 2003). You don’t want seahorses eating frozen Mysis that may have become contaminated from laying on a dirty substrate (Giwojna, Dec. 2003). Using a feeding station can help prevent this as can vacuuming the substrate regularly.
Fortunately, intestinal flagellates have virtually no ability to survive outside their host’s body (Giwojna, Dec. 2003). If you detect the problem early and are diligent about cleaning the substrate while the aquarium is being treated with metronidazole, the parasites should be easily eliminated from your system and chances are good the rest of your herd will remain unaffected (Giwojna, Dec. 2003).
Low numbers of these flagellates are often part of the fish’s normal intestinal flora and only become problematic when a fish is stressed or its immune system is otherwise compromised, allowing them to reproduce unchecked. In this case, long-distance shipping and the stress of adjusting to a strange new aquarium appear to have tipped the balance in favor of the intestinal flagellates, but a regimen of metronidazole should resolve the problem.
Your local fish store should carry a medication designed for aquarium use whose primary ingredient is metronidazole (e.g., Seachem Metronidazole, Flagyl, Metro-MS by FishVet, Hexamit, etc.). Just follow the instructions on the package and be sure to use the marine dose. Temporarily relocate sensitive invertebrates such as decorative shrimp until after the treatment regimen has been completed.
That’s the rundown on treating intestinal flagellates with metronidazole, Michael.
In addition, it would be best to consider some additional measures that may help to stimulate the seahorses’ appetite.
As you know, it’s important to fatten up the skinny seahorse that has stopped eating as soon as possible in order to keep its strength up. The best way to do that is to line up some choice live foods to tempt your reluctant feeder to eat more aggressively, Michael, but you may not be able to obtain suitable live foods locally, so you may need to order them and have them delivered to you.
If that’s the case, go ahead and order some of the seahorse’s favorite live foods, and I will explain of few other steps you can take it immediately to help restore its appetite while you are waiting for the live foods to arrive.
First of all, you should perform a major water change to assure that your water quality in the seahorse tank is optimum and that there are plenty of minerals and trace elements in the water, and you should increase the surface agitation and aeration in your seahorse tank immediately to increase the levels of dissolved oxygen and decreased the levels of dissolved carbon dioxide in the water. Low oxygen levels are one of these environmental problems that can cause a seahorse to suddenly stop eating, Michael.
Finally, get some Seachem Garlic Guard from one of your local fish stores and begin using it with the frozen Mysis right away, sir. The Garlic Guard acts as an appetite stimulant so adding it to the frozen Mysis may trigger a feeding response from your thin female. Call around to the pet shops and fish stores in your area and you should be a will to find one that carries products from Seachem Laboratories, including the Seachem Garlic Guard.
Here is a more detailed explanation of the steps you should take whenever one of your seahorse suddenly stops refusing food, including good sources where you can obtain choice live foods online and instructions on how to use the Seachem Garlic Guard properly, Michael:
Loss of Appetite & Hunger Strikes
An unexplained loss of appetite in an otherwise healthy seahorse is also often an environmental problem. Many times such eating problems are due to low levels of dissolved oxygen or high levels of carbon dioxide, and they can frequently be caused by deteriorating water quality, especially deficiencies in certain minerals and trace elements. Lack of appetite is therefore often an early indicator of water quality problems.
When a seahorse goes off its feed, the first things to consider that will often help restore its appetite are to perform a series of water changes to restore water quality and to try tempting the seahorse with live foods, as discussed in greater detail below:
For starters, I have listed some of the factors that are commonly known to contribute to a loss of appetite in seahorses:
(1) deteriorating water quality.
(2) low oxygen and/or high CO2 levels.
(3) a deficiency of trace elements and minerals.
(4) various disease processes — in particular, internal parasites.
Regardless of how your water chemistry appears right now, a good place to start addressing loss of appetite is to one or more 25%-35% water changes immediately to safeguard the water quality and replenish depleted trace elements and minerals. (At first glance your aquarium parameters may look great, but there are some water quality issues that are difficult to detect with standard tests, such as a decrease in dissolved 02, transitory ammonia/nitrite spikes following a heavy feeding, pH drift, a deficiency and trace elements/minerals, or the gradual accumulation of detritus. A water change and cleanup is a simple preventative measure that can help defuse those kinds of hidden factors before they become a problem and stress out your seahorses. These simple measures may restore your water quality as well as your seahorses’ appetite.)
Be sure to check your dissolved oxygen (O2) level in addition to the usual pH, ammonia, nitrite and nitrite readings.. A significant drop in O2 levels (6 – 7 ppm is optimal) or rise in CO2 levels is very stressful yet easily corrected by increasing surface agitation and circulation to promote better oxygenation and gas exchange. Add a shallow airstone just beneath the surface if necessary and increase the circulation throughout your tank it possible.
Whether the beneficial effects are due to improving water quality or replenishing depleted trace elements or something else altogether, performing a major water change, or a series of water changes, as described above often sets things right when seahorses are off their feed for no apparent reason.
In the meantime, while you are working on your water quality, by all means get some live foods to tempt your finicky seahorse and see if you can fatten it up a bit. When a seahorse stops eating, the most important thing is to get some food into him one way or another. You’ve got to keep his strength up and give him a chance to recover before you can worry about weaning him back onto frozen foods again. Hawaiian red feeder shrimp or volcano shrimp (Halocaridina rubra) are ideal for this — seahorses find them utterly irresistible! But anything that’s readily available — enriched adult brine shrimp, live ghost shrimp that are small enough to be swallowed, newborn guppies or mollies, Gammarus amphipods, copepods, you name it — is worth a try. Just get some good meals into the reluctance seahorse ASAP anyway you can to build up its strength and help it regain its conditioning.
The problem may simply be a hunger strike, especially if you are dealing with a wild-caught seahorse that is dependent on live foods. When a wild seahorse suddenly stops eating, many times it has simply lost interest in frozen foods. Although this is rarely a problem with domesticated seahorses that are accustomed to eating frozen foods from an early age, hunger strikes are common developments when keeping wild-caught seahorses. If so, providing live foods, at least temporarily, will often turn the situation around.
When seahorses tire of the same old, boring frozen food and refuse to eat their “veggies,” living prey is what they crave: Mysids, feeder shrimp, Gammarus or adult Artemia — the type of food isn’t really as important as the fact that it’s alive and kicking. Nothing stimulates a sea horse’s feeding instincts like the frantic movements and evasive maneuvers of real, live, “catch-me-if-you-can” prey items (Giwojna, 1996).
That’s why I like to use occasional treats of live food as behavioral enrichment for my seahorses. They get the thrill of hunting after and chasing down live prey, which livens things up for them in more of ways than one and is a nice change of pace from their daily routine in captivity. Live foods are guaranteed to perk up an ailing appetite and excite the interest of the most jaded “galloping gourmets.” When it comes to a hunger strike, living prey is the only sure cure for the “Bird’s Eye blues.” (Giwojna, 1996)
I also find live foods to be especially useful for those rare occasions when seahorses are ailing and must be treated. Many medications (e.g., Diamox) have the unfortunate side effect of suppressing appetite, so when treating sickly seahorses, it’s a good idea to tempt them with choice live foods in order to keep them eating and help build up their strength while recuperating. Separating an ailing seahorse from its mate and herdmates and transferring it to a strange new environment for treatment can be a traumatic experience, especially since the Spartan surroundings in the sterile environment of a sparsely furnished hospital tank can leave a seahorses feeling vulnerable and exposed. Live foods can counteract these negative affects to a certain degree, and offer a little excitement that distracts the isolated seahorse temporarily at least from its melancholy.
Some of the choice live foods that sea horses find irresistible are Ocean Rider’s red feeder shrimp (Red Iron Horse Feed, Halocaridina rubra), Gammarus amphipods, and the live Mysis post-larval Feeder Shrimp from Sachs Systems Aquaculture or Drs. Foster and Smith (liveaquaria.com). These live bite-size crustaceans are what I’d like to call a “feed-and-forget” food. They are tough, rugged little shrimp that you can toss in your tank with no acclimation whatsoever. They are agile and elusive enough that your filters won’t eat them and the seahorses won’t be able to capture them all right away. Some will hide and evade well enough that your seahorses will still be hunting down the stragglers for the next day or two. Best of all, you can toss a nice batch of them in your aquarium, secure in the knowledge that they won’t perish and pollute it, but thrive and survive as real, live, “catch-me-if-you-can” prey items that seahorses cannot resist.
When a seahorse goes off its feed, providing it with choice live foods can buy you time and stave off starvation while you work on making the water changes to assure optimal water quality for your seahorses.
The Ocean Rider Aquaculture Facility in Hawaii (http://seahorse.com/) is a good source for the following live foods:
Green Iron Horse Feed (Gammarus amphipods)
Red Iron Horse Feed or Volcano Shrimp (Halocaridina rubra)
Or the live Mysis from Sachs Systems Aquaculture would also be a good choice for this. You can obtain 200 live Mysidopsis bahia for around $35 from Sachs and your seahorses will love them:
Likewise, the live Mysis or post-larval Feeder Shrimp from Drs. Foster and Smith would also be a good alternative for you, Michael. You can obtain 100 live Mysidopsis bahia for $33.99 or 100 bite-size Feeder Shrimp for $39.99 from liveaquaria.com and your seahorses will love them. Just copy the following URL (everything within the angle brackets below), paste it in your web browser, and press the “Entered” key, Michael, and it will take you directly to the right webpage:
Some hobbyists have good success coaxing a finicky 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 portion of live feeder 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 bite-size feeder shrimp passing within striking distance of the hungry seahorse. If the affected seahorse is still interested in feeding at all, then releasing it in an in-tank enclosure like this where it will be surrounded by plenty of tempting live feeder shrimp and can feed at its leisure may help it to keep its strength up and recover more quickly. Add one or two hitching posts within the critter keeper or breeder net so that the seahorse can anchor in place and wait for a tasty shrimp to pass within easy reach, and give him an hour or two within the enclosure to eat his fill of the feeder shrimp. You can monitor his progress from a nonthreatening distance away from the tank to see how he 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.
If your seahorse’s loss of appetite is associated with a change in its fecal pellets, that could indicate a problem with internal parasites. For example, a change from fecal pellets of normal color and consistency to white, stringy mucoid feces accompanied by hunger strike is often an indication of intestinal flagellates (Kaptur, 2004). If you think that this could be a factor in your case, then treatment with metronidazole or praziquantel is usually an effective remedy (Kaptur, 2004).
Okay, that’s the quick rundown on some of the things you can do immediately to perk up your seahorse and restore her appetite to normal again, Michael. You should immediately perform a major water change and increase the surface agitation and oxygenation in your seahorse tank. Go ahead and install an airstone, air diffuser, air bar, or bubble wand in your seahorse tank positioned where the stream of bubbles will not be drawn into the intake for the filtration system and that may be all you need to do to resolve the situation for now. By all means, line up some choice live foods to tempt her to eat as well.
For the time being, be sure to get the Seachem Garlic Guard to use with the frozen Mysis as an appetite stimulant, which is something that you can try right away that may help to restore your seahorse’s appetite and encourage it to feed more aggressively, sir.
Finally, when the seahorse is eating frozen Mysis readily again, I recommend switching to Vibrance 1 for the time being. The original Vibrance (i.e., Vibrance 1) is a high-fat formulation rich in lipids, and is excellent for helping to fatten up and underweight seahorse.
Best of luck resolving the situation and getting your skinny seahorse back to normal again, Michael.
Pete Giwojna, Ocean Rider Tech Support