Seahorse fry

Dear Eric:

Congratulations on the batch of newborns!

I’m sorry to hear that your first brood of seahorse fry didn’t fare better, sir, but that’s not unusual. There is always a steep learning curve when it comes to rearing the newborns, and it’s quite common — perhaps even the rule — for the home breeder to lose the entire brood during his first few attempts at rearing.

So you are doing well to have saved three of the newborns from an unexpected brood of babies, Eric. As you refine your methods and become more proficient at providing suitable live foods for the newborns and work out the feeding regimen that’s most efficient for your particular circumstances, your results will get better. You will have more of the fry surviving for longer periods, until eventually you are able to raise a few of the fry from a few of the broods to maturity. It’s just a matter of patience and hard work, Eric — there simply are not a lot of shortcuts that are helpful when you’re trying to raise baby seahorses.

Be prepared for additional broods of babies, Eric. Once a pair of ponies begin breeding, if conditions are favorable, they will often continue to churn out brood after brood of young every 3-4 weeks or so.

I have the wealth of information on rearing newborn seahorses that would be useful for you, sir, but the bulk of the material is way too extensive to be posted on this discussion forum. However, if you contact me via e-mail at the following address, I will be happy to send you the additional information as an attachment to an e-mail, sir.

Once you get your brine shrimp hatcheries cranked up and running in high gear, Eric, you’ll need to maintain frequent feedings in order for the newborns to do well. I’ve outlined the recommended fry feeding schedule for you below, which is based on Tracy Warland’s fry feeding regimen as a professional breeder. When looking over these recommendations, bear in mind that the home hobbyist almost always needs to be more concerned about underfeeding than overfeeding (it’s ordinarily only the pros that worry they might be feeding their fry too much). The humble home breeder will have his or her hands full just trying to keep up with the endless appetites of all those fry.

With that in mind, here are some suggestions and information to serve as guidelines when getting your rearing program started, Eric:

Fry Feeding Schedule

When feeding baby brine shrimp (bbs) or Artemia nauplii to seahorse fry, you want to avoid overfeeding (feeding them too much at a single feeding) as well as feeding them newly hatched bbs which have depleted their yolk supply and are nutritionally barren. The best way to do that is provide the fry with many small feedings throughout the course of the day, each of which they can clean up fairly quickly, rather than one or two massive feedings.

I suggest feeding the fry 3-5 times daily, at least 2-3 hours apart. When you are feeding the right amount, the fry should consume most of the nauplii within the first 20-30 minutes, but give them 3 hours to finish the rest and digest it fully before you feed them again. Ideally some brine shrimp will remain throughout each 3-hour feeding session, albeit at a greatly reduced feeding density after the first half-hour.

In other words, your ideal fry feeding schedule should go something like this: 8 AM feed, 11 AM feed, 2 PM feed, 5 PM feed, 8 PM feed, lights out at 11 PM. Harvest the baby brine shrimp for each feeding session in succession from each of the jars you started hatching at 3-hour intervals. This will assure that the Artemia nauplii you are feeding to the fry are no more than 3 hours old and thus at the peak of their nutritional value.

Like all babies, seahorse fry exist only to eat and poop. To say they are voracious is a gross understatement — at this stage of their development, the newborns have but one mission in life: to eat and thus to grow. Researchers have found that a single seahorse only a few weeks old can consume 3000-4000 newly hatched brine shrimp in a single day! Milligram for milligram, a great white sharks feeding habits appear downright dainty and positively anorexic compared to a baby seahorse on the prowl for live prey. And as you can imagine, when well-fed fry eat that much, defecation is amazingly rapid, with each newborn producing an average of one fecal pellet every 25-30 minutes.

One of the many quirks of seahorse anatomy is that they lack a true stomach like ours with the capacity to store food between meals (Bellomy, 1969). Rather, they are endowed with a rudimentary “stomach” that is little more than a pouchlike expansion of their intestine with no distinct separation between it and the rest of their digestive tract (Tamaru, Aug. 2001). Food passes continuously through this simple stomach instead of being stored therein. This is an adaptation to a sedentary lifestyle in which seahorses feed while at rest (as ambush predators that wait for their prey to come to them) more or less continuously throughout the daylight hours, rather than storing food or stockpiling energy in fat reserves (Tamaru, Aug. 2001). And like other carnivorous fishes, their intestinal tract is also relatively short (Tamaru, Aug. 2001).

Therefore, think of their digestive tract as a short continuous tube. When a seahorse is full, nothing more can be taken in at one end of its digestive tract without something being passed out of the other end. Seahorse fry don’t stop eating once they are full — the feeding instinct of these seagoing gluttons is so strong it compels them to keep eating as long as suitable prey is present. Baby seahorses, not sharks, are the ocean’s “remorseless eating machines!”

When they are overfed, particularly on hard-to-process Artemia nauplii, food passes through their system too fast to be digested properly. Because they swallow their prey whole and intact, this can actually reach the absurd point where they are passing live Artemia in their fecal pellets (Warland, 2003)! When that happens they are getting virtually no nourishment from their food and are literally starving in the midst of plenty. Here’s how Tracy Warland, a commercial seahorse farmer in Port Lincoln, Australia, describes this feeding dilemma and how to deal with it:

“We feed by looking closely at the ponies feces under a microscope, (a cheap dissecting microscope is ample); we breed 5 different species and all the ponies are the same, in as much as they are total gluttons. Baby seahorses (ponies) will eat so much instar 2 Artemia that they will pass out live Artemia in their feces, and they will of course not get any nutritional value from any feeds, so by over feeding you will starve them to death. We have done this. So if you feed them too much you will just love them to death as they will starve due to inability to digest. We look at the feces to determine the level of digestion and feed accordingly. Usually a feed is what the biomass of the tank can clean up in a 20-minute session, after which we leave them alone for about 2 hours and then feed them again. As soon as they defecate, we use a pipette to gather up the droppings and examine them under the microscope to check digestion levels and adjust our feeding accordingly. This is not necessary for every feed as you can soon learn the quantity required for each feeding; just make sure that the Artemia is digested fully (Warland, 2003).”

So if you have a microscope, you can easily verify that you are feeding enough but not too much at any given feeding by visual examination of the fry’s fecal pellets. Otherwise, you will eventually learn the right amount to feed and how often to feed from experience. The right feeding regimen varies according to species, the size of the brood and the size of your nursery tanks, as well as the type of food you are providing, so it is difficult to make generalizations in that regard. But Tracy Warland recommends the following:

“You need to add enough food for your fry to eat for about 15-20 minutes (75%
of the food should have been consumed within that time). If it is not, then you have added too much. The fry then should have some time to digest this food, about 2 – 3 hours is plenty. Provide at least 3-5 feedings daily. Only feed during daylight hours and turn off lights at night (Warland, 2003).”

As I said, Tracy’s feeding regimen may not be the best option for the home hobbyist, however. The average hobbyist has his hands full just trying to keep up with the demands of a brood of fry, doesn’t have access to a microscope to monitor the fecal pellets of the fry, and generally needs to be far more concerned about underfeeding than overfeeding. The salient point is that when rearing fry, many small feedings daily are vastly preferable to one or two large feedings. Most hobbyists are more successful at rearing when their goal is to assure that the fry have access to at least some food throughout the day. Many breeders accomplish this by adding small amounts of newly hatched Artemia to their nurseries whenever they walk by. For the sake of hygiene and water quality, its important to siphon off the bottom of the nursery tanks between feedings, whether or not you are able to do a microscopic examination of the fecal pellets.

It’s imperative that you work out the most efficient feeding regimen one way or another, since overfeeding is not only bad for the seahorse’s digestion, it also debilitates the fry because it is very energetically demanding for them to pursue prey and eat nonstop all day long (Warland, 2003). With a little experience, you will soon work out the feeding regimen that works best for you.

Many home hobbyists find an alternating 2-hour feeding schedule works well during the day. The fry are allowed to feed for 2 hours, then fasted for 2 hours, then given another feeding and fasted for 2 hours, and so on. The nursery is then darkened overnight and the seahorses are rested.

The general idea is to set up multiple hatching containers so that you can harvest the newly hatched brine shrimp nauplii from a different hatchery for each feeding. Thus, if you’re going to be feeding five times a day (i.e., every three hours throughout the day), then you would set up a battery of five separate brine shrimp hatcheries, and you would start the brine shrimp cysts hatching in each of them at three hour intervals.

The reason you stagger the hatching jars that way, adding the eggs to each at three hour intervals, is to assure that you are feeding the fry newly-hatched Artemia nauplii that have just emerged from their eggs, and therefore are at the peak of their nutritional value, for each of the feedings. Right after the first instar Artemia nauplii have emerged from their shells, their yolk supply is completely intact and they are more nutritious, since when the seahorse fry eat them, they get the benefit of all the nutrients in the rich yolk supply. Several hours after the Artemia nauplii have hatched out, they will have consumed much of their yolk supply and have relatively little nutritional value as a result. So it is very desirable to feed the newborns seahorse fry first-instar Artemia nauplii that have just emerged from their shells, because the nauplii are the smallest at that stage and therefore the easiest for even the undersized fry (i.e., runts) to swallow and more importantly because the newly emerged nauplii retain their maximum nutritional value at that point.

Once the Artemia nauplii undergo their first molt and becomes second-instar nauplii, they have exhausted their yolk supply and develop mouthparts so they can begin feeding on their own. Baby brine shrimp at this stage are larger and and may be too large for the smallest newborns to eat, and the second-instar bbs must be fed or enriched (i.e., gut-loaded) at this stage or they have very poor nutritional value. So the idea is to assure that you are always feeding the newborn seahorses first-instar Artemia nauplii that have just hatched and retain their full supply of yolk.

That’s why it’s important to stagger the start of the hatch in each of the hatcheries. If you started the brine shrimp hatching at the same time in all five of the hatcheries, by the time you did your second feeding of the day, some of the brine shrimp would be three hours old. Likewise, some of the brine shrimp you fed for the third feeding would be six hours old, and some of the brine shrimp you offered at the fourth feeding that day would already be nine hours old, and so on. The older brine shrimp nauplii would have used up more and more of their yolk supply, or already entered the second-instar phase before they were fed to your seahorses, and not have been nearly as nutritious as the brine shrimp you offered for the first feeding that day.

Staggering the start of the hatch in each of the hatching containers therefore allows you to offer primarily newly-hatched first-instar Artemia nauplii with complete yolk supplies at each of the feedings throughout the day. In other words, for the first feeding of the day, you harvest the Artemia nauplii from the hatchery you started first. You harvest the nauplii for your second feeding from the hatching jar you started hatching three hours later, and you harvest the nauplii for the third feeding from the hatchery you added the Artemia cysts to six hours later, and so on.

In short, if you will be feeding your seahorse fry five times a day, your ideal fry feeding schedule should go something like this: 8 AM feed, 11 AM feed, 2 PM feed, 5 PM feed, 8 PM feed, lights out at 11 PM. Harvest the baby brine shrimp for each feeding session in succession from each of the jars you started hatching at 3-hour intervals. This will assure that the Artemia nauplii you are feeding to the fry are no more than 3 hours old and thus at the peak of their nutritional value.

Mustangs and Sunbursts (Hippocampus erectus) readily accept newly hatched brine shrimp as their first food, Eric, so it isn’t strictly necessary to raise copepods for them. However, there is considerable evidence that providing larval copepods for the first few days of life will increase the survivorship of newborn seahorses, so here are some suggestions for culturing copepods if you want to go to the extra trouble and effort.

Culturing Copepods

Marine copepods are the ideal food for rearing seahorses fry. They are a natural prey item that constitutes a large portion of the diet of fish larvae in the ocean, and many marine fishes have evolved efficient feeding strategies for preying on them as their primary foods. This includes seahorses, whose tubular snouts are adapted specifically for feeding on tiny crustaceans such as ‘pods, and which have developed a sedentary lifestyle as ambush predators that allows them to capture them with maximum efficiency and a minimum expenditure of energy. The tiny size of the copepod nauplii allows even the smallest seahorse fry to eat them, and they are a feed-and-forget food that will survive in the nursery tank until eaten. The distinctive swimming style of copepod nauplii triggers a strong feeding response from seahorse fry, and ‘pods have naturally high levels of essentially fatty acids. They are superior to rotifers in all these respects (seahorse fry often reject rotifers because they don’t move in the “right” way and simply don’t trigger their feeding instincts) and I recommend that aquarists who are raising pelagic fry concentrate on culturing copepods.

Seahorse fry alter their diet as they grow (Vincent, 1990). This may be due to the fact that they change microhabits as they develop (e.g., when pelagic fry complete their planktonic stage and begin to feed at the bottom as they begin orienting to the substrate). Or it may simply be due to the fact that they become better hunters and perfect their feeding skills as they grow, thus enabling them to tackle larger, more active prey (Vincent, 1990). Whatever the cause, one good way to keep up with the fry’s changing dietary requirements is by providing them with cultured copepods at progressively later stages of development.

Step 1: Providing Marine Microalgae (Phytoplankton).

Marine microalgae or phytoplankton is available from many sources. It can be cultured at home, and if you have a green thumb and are experienced with such greenwater cultures, that may be your best option. However, home culturing may not be for everyone. Greenwater cultures can be tricky to maintain. They are easily contaminated and are prone to “crashing” suddenly and unpredictably, which can have dire consequences if you are relying on the phytoplankton to provide food for your seahorse fry.

Alas, I am one of those unfortunates who cannot seem to maintain a decent greenwater culture for any length of time no matter what I try. Consequently, I now much prefer to obtain live marine phytoplankton from other sources rather than attempting to culture my own. Commercially available phytoplankton tends to be more concentrated than homegrown cultures as a rule, and I find purchasing it to be far more convenient, efficient, and productive. Given my repeated failures and the time I spent for naught on my own greenwater cultures, I’m certain that buying live phytoplankton is more economical for me in the long run as well. If you are inexperienced with greenwater culture or simply lack the time to culture your own, I recommend buying your live phytoplankton instead (see the Resources page for suppliers). Whichever source you decide to use, home grown or store bought, make sure you use it strictly according to instructions to prevent contamination and spoilage of the phytoplankton.

The type of phytoplankton or microalgae you use is not that crucial. Chlorella is one of the most popular microalgae used in mariculture (Wilkerson, 1995), but Dunaliella also works extremely well and is recommended by Dr. Amanda Vincent (Vincent, 1995c), an authority on the breeding habits of seahorses. Serious breeders often use a mixture of different types of phytoplankton to feed copepods or rotifers, rather than a microalgae monoculture, with the goal of enhancing the nutritional profile of the ‘pods or rotis as much as possible (David Warland, pers. com.).

There is a great deal of merit to that approach, but in the past, maintaining separate cultures of different species of microalgae was beyond the capabilities of most home hobbyists, myself included. I prefer to keep things simple and I have always used Nannochlroposis as the phytoplankton I feed to copepods, both because it produces good results and because it is commercially available from a number of sources. To simplify things all the further, I purchase my Nannochlroposis in quantity as needed, rather than struggling with phytoplankton cultures.

The product I like best at the moment for this now includes a concentrated mixture of live marine phytoplankton (two species of Nannochlroposis, N. oculata and N. salina, as well as a Chlorella sp.) in every bottle (DT’s Live Marine Phytoplankton, 2003). That makes it a simple matter to provide my ‘pods with a diversified diet to maximize their nutritional value as fry food — I just unscrew the cap on the bottle and pour the requisite amount of this phytoplankton mixture into my culture tank whenever it’s losing its greenish tinge, and I’m in business (DT’s Live Marine Phytoplankton, 2003)! No muss, no fuss. Quick, easy and effective — just the way I like it!

Step 2: Culturing Zooplankton (copepods and/or rotifers).

We will be using standard 10-gallon glass aquaria as our batch culture tanks. It’s a good idea to run at least 2 such tanks simultaneously; that way, if one of the cultures falters, the other tank can pick up the slack and you won’t miss a beat. Depending on how many seahorse fry you are rearing, you many need to operate several such tanks to assure you will be producing sufficient food for them all.

Fill each of these culture tanks slightly less than half full with synthetic saltwater, adjust the salinity of the culture tank to match the salinity of your nursery tanks, and maintain the pH at 7.9 or below (Rhodes, 2003). This will assure that the copepods (or rotifers) we are culturing do not experience any salinity shock when we feed them to our seahorse fry. No heater is necessary — the cultures will do just fine at room temperature (24C-28C is optimum). Provide very low aeration (Rhodes, 2003). Airstones are unnecessary — a naked bubbler stem is sufficient. Adjust the airflow so it produces a slow, steady stream of coarse air bubbles (slow enough so that you can count the individual bubbles). Ambient room lighting is adequate or you may provide low wattage fluorescent lighting if you prefer.

Add enough greenwater (either commercially produced phytoplankton you’ve purchased or your own homegrown microalgae) to tinge the culture tanks green, and you’re ready to start culturing copepods. All that remains at this point is to “seed” the culture tanks with copepods. Add a starter culture of marine copepods to each tank, acclimating the ‘pods if necessary exactly as you would acclimate a new aquarium fish. They will do the rest.

To nurture the copepods, simply maintain a nice green tint to the culture water by adding more phytoplankton whenever the water in the tanks begins to clear in color. (Be conservative with these phyto-feedings. One dose of phytoplankton every 7-10 days is generally adequate, depending on production and your copepod harvest rates; Rhodes, 2003.) The ‘pod population in the culture tanks will double every 2-3 days, depending on the temperature and how well they are fed (Rhodes, 2003), and as soon as the population builds up sufficiently, we can begin to harvest copepods to feed to our seahorse fry. When you begin to notice numbers of copepods gathering on the tank glass, that’s a good indication that their population density can support daily harvesting.

The best way to harvest copepod nauplii is to strain the desired amount from the culture tank using a 35-micron sieve and then rinse or backwash the strainer in the nursery tank (Rhodes, 2003). Alternate which culture tank you harvest the copepods from for each feeding in order to avoid depleting the ‘pod population too much in any given tank.

Periodically, it will be necessary to restart the copepod culture tanks to filter out the detritus that accumulates on the bottom. This is typically done every month or two (Rhodes, 2003) and is a surprisingly simple process. Just siphon out the water from the culture tank, straining the water in the process in order to retain the copepods. A 125 -micron sieve works well for a strainer. That size mesh will retain all the reproductive adults you need to restart your culture (Rhodes, 2003). It’s a good idea to use a small diameter siphon at first, being careful to suck up as little of the detritus as possible since it will clog up your strainer and your goal at this point is to recover as many copepods as you can. Once you’ve strained out most of the ‘pods, backwash them into container of clean saltwater and set them aside to seed the culture tank after you’ve finished cleaning it. Having saved as many pods as possible, switch to a larger siphon and drain the culture tank completely, removing all of the accumulated detritus. Fill the tank half way with freshly mixed saltwater you’ve prepared in advance and adjust the aeration. Then return the copepods you strained out previously and add enough concentrated phytoplankton to tinge the water green, and your culture is ready to begin producing again. If you restart your culture tanks on alternate months, one or more of them will be in full production at all times, and you can keep a thriving copepod population going indefinitely in this manner.

If you so desire, rotifers can be cultured in exactly the same manner. The only difference is that the 10-gallon culture tanks should each be seeded with a quart of live rotifers initially (Giwojna, Jan. 1997). When necessary, add enough concentrated phytoplankton or greenwater to keep the rotifer culture tanks slightly green. As long as the rotifers are being fed algae, about 25% of the rotifer cultures can be harvested each day to feed to your seahorse fry (Wilkerson, 1995). Try to keep more than one rotifer culture going at all times in case of crashes, and be sure to keep the bottom of the culture tanks scrupulously clean (Giwojna, Jan. 1997).

In fact, you can even maintain a dual culture of copepods and rotifers in the same tank if you wish. But you must avoid cross-contamination of your culture tanks with brine shrimp at all costs! Newly hatched brine shrimp (Artemia nauplii) are considerably larger than either copepods or rotifers, and the Artemia will happily fed on them as well as the phytoplankton. So if any brine shrimp ever find their way into your culture tanks, you will very shortly thereafter be culturing Artemia instead of ‘pods or rotis, leaving you with nothing but live food that’s too large for pelagic fry to eat.

Harpacticoid copepods such as Nitokra lacustris go through 6 naupliar stages as they grow, followed by 6 copepodite stages, before they become reproductive adults. They range in size from 45 microns (smaller than rotifers) up to 270 microns as full-sized adults. The many different stages of development copepods undergo is actually a blessing for the aquarist since it makes it possible to provide progressively larger ‘pods to the seahorse fry as they grow simply by using sieves with different sized mesh to harvest them. For instance, a 35-micron sieve will gather up even the smallest copepod nauplii for newborn fry, while a 125-micron will collect only adult-sized pods for older fry and juveniles, leaving the smaller ‘pods behind to develop further. An 80-micron sieve will take intermediate-size ‘pods along with the adults.

Whether you’re culturing rotifers or copepod nauplii, pelagic seahorse fry should be fed continuously starting 6-12 hours after birth (Giwojna, Jan. 1997). Dr. Amanda Vincent recommends feeding 2 plankton nets of rotifers (or ‘pods) 5-7 times daily or whenever no plankton is visible in the nursery tanks (Vincent, 1995c). In addition, she keeps a drip of diluted plankton (i.e., rotifers or copepods) going at the rate of 10 liters/day at all times (Giwojna, Jan. 1997). (A bucket of copepod-laden or rotifer-rich saltwater set on top of the nursery tank will suffice for this–just use a length of airline tubing as a siphon and adjust the drip rate with a valve; Vincent, 1995c.)

Your youngsters still have a ways to go before you can think about weaning them onto frozen foods, Eric. Professional breeders will begin weaning when the juveniles are about a month old, but home hobbyists typically need to postpone any we needed tabs until the fry are six weeks old or older for good results.

A good rule of thumb to keep in mind is that once the juveniles are 1-1-/2 inches in length, they need a more substantial diet than newly hatched brine shrimp, and they are ready to be weaned onto frozen foods. They should be receiving brine shrimp at advanced instars, including adult brine shrimp, at this size, and you should begin weaning them onto minced frozen Mysis and other frozen foods at this point, as discussed below.

Making the Transition to Frozen Foods

The current thinking is that the fry can remain on a steady diet of newly hatched Artemia until you are ready to begin weaning them onto a diet of frozen foods (usually minced Mysids and/or Cyclop-eeze). Aquaculturists are now converting the fry to frozen foods earlier than ever, often beginning around 3-4 weeks old. Jeff Mitchell reports that the fry are healthier and grow faster the sooner they make the transition to enriched frozen foods, and he expects the young seahorses to have made the transition to frozen foods by the age of 4-1/2 weeks.

I generally have the best results using frozen Mysis. The best way to prepare the Mysis for the juvenile seahorses is to mince the frozen Mysis coarsely rather than putting it through a blender. How fine or coarse you need to chop it depends on the size of your fry, since you want to wind up with bite-size pieces of Mysis. Initially, many breeders prefer to shave small pieces of Mysis off of a cube while it’s still frozen.

The frozen Mysis that works best for most hobbyists is Hikari in frozen blocks rather than trays. The Hikari Mysis is much smaller than Piscine Energetics Mysis relicta and that makes it easier to shave off bite-sized pieces for the young seahorses. Some hobbyists report even better results using the new Mini Mysis offered by H2O Life, which is small enough that it often doesn’t need to be minced or shaved before offering it to the juveniles.

When it comes to shaving the Mysis, a technique that works well for many home hobbyists is to use a potato peeler to shave off bits of the Hikari Mysis from a frozen block, and then use a single edged razor blade to further mince the frozen bits the potato peeler has removed.

Try offering the minced Mysis exclusively for their first feeding of the day when the youngsters are the hungriest. Watch the juveniles closely to see if any of them begin to pick at the minced Mysis or pick it up from the bottom. If they still aren’t having any of it, siphon up the uneaten frozen Mysis after about half an hour and offer them newly hatched brine shrimp soaked in Mysis juice so that they have something to eat, and intermingle some freshly minced Hikari frozen Mysis or Cyclop-eeze in with the bbs.

When the fry have grown a little larger and can accommodate bigger pieces of Mysis, I find it convenient to carefully thaw whole Mysis individually and then carefully chop them into several pieces. Or the Mini Mysis by H2O Life can be fed to the larger juveniles whole and intact, if you can obtain it.

Either way, it is very important to be extra diligent about vacuuming up leftovers (and any fecal pellets) while the fry are making the transition to frozen Mysis. Otherwise, the minced Mysis that doesn’t get eaten right away while it’s still suspended in the water column or shortly after it has settled on the bottom will begin to degrade the water quality in your nursery tank.

It’s important to overlap the fry food when they are making the transition. Offer them shaved or minced Mysis along with the newly hatched brine shrimp they are accustomed to eating. (Many times it’s better to offer the minced Mysis first, while the fry is still the hungriest, and then add the baby brine shrimp.) Once they begin eating the bits of frozen Mysis well, gradually increase the amount of minced Mysis and decreased the amount of baby brine shrimp you offer at every feeding until they are finally eating the shaved Mysis almost entirely.

Overlapping the feedings this way, offering newly-hatched brine shrimp as usual along with just a little frozen Mysis at first, assures that there is familiar food available to the fry while they are making the transition and makes sure that the slow learners still get enough to eat.

Some hobbyists find it helpful to begin soaking the newly hatched brine shrimp in Mysis juice for a week or two before they actually began offering the bits of minced Mysis along with the bbs. That way, the juveniles get used to the scent of the frozen Mysis and associate it with food before you start to add the bits of frozen Mysis.

Here’s a previous message from Patti that describes how she weaned her erectus fry onto frozen to Hikari Mysis:

[open quote]
I’m wondering if nutrition is your problem.
Could you train them onto frozen mysis? My 4 week old erectus are eating shaved Hikari frozen mysis already. They started not eating much of the BBS and looking around the bottom of the bowl. I enriched the shaved mysis w/Vibrance & put it in the bowl. It goes to the bottom and they’re on the hunt. They’ll look at it a good while and then snick. It only took 1 day to train them. I swish it around a little at first to get them interested.

I think the mysis is better for them nutritionally and they don’t have to spend so much energy eating all those tiny BBS. Give it a try. It may take a few days. I gave mine the mysis 1st – before adding the BBS. That way they were pretty hungry. Then I gave them some BBS for desert to make sure each one got something to eat if they weren’t eating enough mysis yet.
Patti [close quote]

Notice that Patti’s erectus fry were all hitching and beginning to look around on the bottom for things to eat, indicating that they were ready to give up their planktonic existence (i.e., the high-risk pelagic phase) and make the transition from live brine shrimp suspended in the water column to frozen foods.

Other breeders go a step further and begin adding a little of the minced Mysis to their nursery tanks with the newborns right from the start to help build up their intestinal flora and ultimately enable them to better digest the frozen Mysis when they start eating it. They feel that this helps the babies get them used to the scent of the Mysis and conditions them to associate it with food, which helps to make the transition from live food to frozen Mysis easier later on when they’re the right age.

For example, here’s how Neil Garrick-Maidment, a very successful breeder in the UK, describes this technique:

Hi Peter and all,

I tend to put in a very small amount of finely chopped mysis in with the fry from day 1. The idea behind this is to create a bacterial soup in the fry water to help load the fry gut with the right bacteria to break up the mysis shrimp which tends to be quite hard. It makes it easier to get them to switch to dead mysis later on BUT it is crucial to clean the tank daily and water change to stop a problem with disease..

Neil Garrick-Maidment

Cyclop-eeze is also worth considering when weaning the youngsters onto frozen fare. When the juveniles are the right age, don’t hesitate to try them on frozen Cyclop-eeze first if you aren’t having any luck with the frozen Mysis. Lelia Taylor is one hobbyist who has had good results using the Cyclop-eeze, as she described below:

<open quote>
I have had success placing BBS in Cyclop-eeze, then feeding the mixture to my babies. They readily take the Cyclop-eeze. As they get bigger I add frozen, enriched brine shrimp. they began eating the frozen food immediately. Using the same principle, I began adding Mysid shrimp, along with the brine shrimp and Cyclop-eeze. I have found, even very young babies, will pick the larger pieces of Mysid shrimp, into bite sized pieces. I have also had success culturing copepods in my baby and grow up tanks. The babies readily feed on these, as well. <close quote>

Hobbyists who have tried The Cyclop-eeze for their juveniles are unanimous in saying that the frozen Cyclop-eeze is far superior than the freeze dried product for this purpose. They report that the bars of frozen Cyclop-eeze in particular work well because they will shed copious amounts of the bite-size frozen cyclops into the water.

Bonus tip: adding one or two older juveniles that are already eating the frozen Mysis well to the nursery tank along with the inexperienced fry in order to act as their mentors can hasten the transition. Many hobbyists report that fry learn to take frozen minced mysids much faster and easier when they are provided with teachers to show them the way. These teachers are usually a few of the older fry from a previous brood, which have already become proficient at feeding on the frozen mysids (Liisa Coit, pers. com.). The younger fry are quick to copy them, learning from their example.

Okay, Eric, that’s the quick rundown on rearing seahorses and eventually weaning them onto a diet of frozen Mysis. It can be tricky weaning the juveniles onto a staple diet of frozen Mysis, and you need to be prepared to make water changes and to be very diligent in cleaning up the breeder net and uneaten shaved Mysis while the youngsters are getting the hang of it. But once they are weaned onto frozen Mysis, the juveniles will grow rapidly and will be ready to introduced to the main tank within 2-3 months or less.

Best of luck with your Sunbursts and their future progeny, Eric!

Happy Trails!
Pete Giwojna, Ocean Rider Tech Support