Nutrition Part IV: Feeding & Rearing the Seahorse Fry

Seahorse Nutrition Part IV: Feeding & Rearing the Fry
by Pete Giwojna – from the January 1997 issue of Freshwater and Marine Aquarium magazine (FAMA)

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In the first three segments on “Sea Horse Nutrition” (Parts I-III), you learned how to provide Hippocampines with a healthy, balanced diet consisting of assorted live foods, a wide variety of frozen foods, and carefully-selected, bite-sized morsels fed by hand. Sea Horses breed more readily in captivity than any other marine fishes, and a nutritious diet such as this will keep mature specimens in top breeding condition.

Healthy, well-fed adults will reward the aquarist with a delightful three-day courtship ritual, culminating in the formation of a permanent pair bond. Most sea horse species mate for life and a pair-bonded couple will soon establish a regular breeding cycle in the aquarium, producing a new brood every two, four, or six weeks. (The gestation period varies with the species and is often correlated with the lunar cycle so that the fry are delivered during the highest tides10, which helps disperse the young.) Males typically mate again within hours of delivering their latest brood11, so the successful sea horse keeper is apt to have a new horde of hungry horselets on his hands every few weeks.

This sole purpose of this article is to help the harried hobbyist handle this happy situation. It will discuss the best ways to meet the demands of several hundred baby sea horses, each of which can consume 3,000-4,000 newly-hatched brine shrimp every day3! I know it sounds like a daunting task, but the techniques explained herein will give every aquarist a fighting chance to raise at least a portion of each spawn.

Since sea horse fry do not to be fed for 24 hours after they are born11, the first lessons will concern how to safely handle the delicate newborns and transfer them from the paternity tank to suitable quarters for rearing.

To successfully raise sea horses, preparations to feed and house the fry must begin well before the brood is due. Start by setting up two or more nursery tanks, depending on how many babies you expect to be raising. The rearing tanks can be small–2 gallon aquaria or 2-1/2 gallon drum fishbowls will do nicely. They should be filled with water taken from the ”paternity ward”–the same tank the fry will be born in–so the delicate newborns can be transferred directly to the nursery without adjusting to any stressful changes in pH or salinity.

Baby sea horses are positively phototrophic11 (attracted to light), and it is important to darken the back walls and sides of the nursery tank that are nearest the light source in order to provide them with definite boundaries and help the fry to orient themselves. This can be done by attaching black construction paper or a dark-colored aquarium backing to the glass and slightly shading the overhead reflector at the rear. Otherwise the fry may cluster at the rear corners of the tank–which tend to be the brightest areas–and exhaust themselves attempting to swim through the glass towards the reflected light. When they find their path blocked by an invisible barrier, they become confused and disoriented, and neglect to feed as they waste their energy struggling against the glass11 .

The nursery tanks should be equipped with suitable holdfasts, a medium airstone, and nothing else. It is important that the airstone is neither too fine nor too coarse. The fry may swallow excessively fine bubbles, mistaking them for food, whereas large bubbles can severely buffet the delicate newborns, causing serious injury or death9. If possible, it’s a good idea to shield the airstone by enclosing it within a screen or perforated tube.

Cured ”sea horse trees” make good hitching posts, as do artificial aquarium decorations such as small seafans and soft plastic plants with fine, branching leaves. If necessary, the holdfasts can be secured to the bare glass with silicone aquarium cement or suction cups designed for use in marine aquaria.

If you can obtain it, live Caulerpa will help maintain good water quality by removing excess nitrates, as well as providing natural hitching posts that help sea horses feel right at home. These marine plants grow from woody holdfasts and don’t need to be anchored in a sand or gravel substrate.

However, hydroids and miniature jellyfish (the free-swimming hydromedusae stage of the hydroids) are often present on live marine plants, and they can become a menace to newborns sea horses9 if introduced to the nursery tank along with the Caulerpa. Not only will they compete with the fry for food, their stings can be lethal to the babies11. Briefly rinsing the plants with tap water before they are placed in the aquarium will eliminate these unwelcome hitchhikers, and they can be removed from the nursery tank by wiping the glass with a sponge.

Good lighting is also essential for the nursery tanks. The fry must be able to see the tiny organisms they live on clearly in order to feed efficiently. Use ”Daylight” fluorescents and leave them on for a minimum of 14-17 hours a day, since the fry need to eat for at least 14 hours everyday11. Some breeders provide the young with 24 hours of light a day so they can feed continuously around the clock during the crucial first 6 weeks of their lives9.

The nursery tanks must be prepared well in advance because, once the brood arrives, all hell breaks loose. In fact, the problems often begin even before the aquarist realizes the fry have been born. Gravid males normally give birth in the early morning hours10, and the hapless hobbyist is apt to be confronted with his first crisis immediately upon arising in the form of a writhing mass of newborn sea horses, hopelessly tangled together at the top of the tank2.

This dangerous situation develops because a newborn’s first instincts are to head to the surface to fill its air bladder and then to anchor itself to something solid. In the vastness of the ocean this is not a problem, since strong currents rapidly disperse the young, but in the confines of an aquarium, the first hitching post it finds will very likely be the tail or snout of one of its siblings. The same mistake is apt to be repeated by the rest of the fry, as they cluster at the surface, until the entire spawn is snarled together tail-to-tail, head-to-tail, tail-to-snout and so on. Once locked together in this Gordian knot, the babies are unable to feed and are doomed to slow starvation unless the aquarist intervenes2.

The best way to deal with this lethal logjam is to gentle disentangle the baby sea horses, one by one, if necessary. This will give you an opportunity to examine each of the newborns individually, and you should begin culling the fry as you separate them from the tangle.

Start by eliminating any stillborn young (up to 1/3 of the entire spawn are born dead in some cases1). Other newborns will be alive but still attached to their yolk sacs, and some of the fry will have obvious deformities. These ”preemies” and crippled specimens must also be weeded out since their chances for long-term survival are very poor.

Next remove all of the undersize individuals (less than 1.0 cm) that are too small to accept Artemia nauplii for their first food. Runts are at a serious disadvantage compared to their larger siblings primarily because their bigger brethren benefit from increased feeding opportunities. Not only can they swallow larger prey, they can swim further with less expenditure of energy. This allows them to feed on a greater range of potential prey and to capture food more efficiently than the small fry.

Continue the process of elimination with the goal of selecting only the healthiest, most vigorous young for further rearing. The idea is to decide how many fry you can reasonably hope to care for, and then cull mercilessly until you reach that number.

It sounds cruel, but the colossal task ahead is going to stretch your time, equipment and patience to the breaking point, and your limited resources must be reserved for the fry that can benefit from them the most. The harsh fact is that if you try to save the entire spawn, you will almost certainly lose them all. It’s far better to keep a few well-fed babies in pristine water and perfect health than it is to keep a few hundred malnourished fry under crowded conditions, in water of rapidly deteriorating quality, that are certain to languish and die2.

After culling, the remaining fry should be transferred into the waiting nursery tanks. NEVER lift the babies out the water when transferring them. They will swallow air and develop fatal buoyancy problems that leave them bobbing helplessly at the surface, unable to submerge or eat11. Exposing the newborns to the air is one of the most common mistakes inexperienced breeders make, and it often results in the loss of the entire brood. The proper way to move the babies is to carefully scoop them up in a small cup or bowl, and gently immerse the cup in the nursery tank to release the fry.

Since the nursery tanks have no filtration, daily water changes are the only way to keep up with the metabolic wastes and oxygen demand of several dozen baby sea horses and the thousands of brine shrimp needed to feed them. When the fry are well fed, defecation is amazingly rapid, with each newborn producing an average of one fecal pellet every 25-30 minutes3. The best way to perform the necessary maintenance is to use a length of airline tubing to siphon off the bottom of the nursery tanks twice a day (morning and evening are ideal for this). Replace the water that was removed while siphoning with freshly mixed saltwater that has been pre-adjusted to the same temp and salinity as the rearing tank. Change about 10% of the water each time you siphon the bottom, so that a total of at least 20% of the water in the nursery tanks is exchanged every day.

Depending on the number of young involved, dividing the brood between 2, 3, or more small tanks is much preferable to rearing the entire spawn together in a single large aquarium. Breaking the brood into smaller groups is a good insurance policy against the disease outbreaks and pollution problems that are a constant danger when you’re working with countless fry under crowded conditions. Should an epidemic of Cryptocaryon erupt in one of the nurseries, or if the water chemistry suddenly turns sour in an overtaxed rearing tank, there is no need for all of the young to be affected2.

As opposed to a single large rearing tank, several smaller nursery tanks are also advisable because they make it easier for the fry to eat. The nauplii will be concentrated in a smaller volume of water, and the feeble fry won’t have expend as much energy chasing after their prey. And it is certainly simpler to make 10-20% water changes in a 2-gallon tank than a 10-gallon tank, making the aquarist less likely to skimp on maintenance.

Once the fry have been culled and transferred to suitable nursery tanks with clean water, rearing becomes a matter of providing the newborns with enough to eat. There are two primary feeding systems in common use today for raising sea horses–a simple system, which any aquarist can confidently attempt, and a more complicated method, which requires greater expertise and is better suited to advanced aquarists. The simpler method relies on newly-hatched Artemia nauplii as the basic diet for the fry, and involves setting up a battery of brine shrimp hatcheries to produce the nauplii in endless amounts. The more complex system simulates the natural food web, and involves growing microalgae, which is then used to culture zooplankton (Branchionus rotifers) , which is in turn fed to the sea horse fry. After 1-2 weeks on a strict diet of rotifers, the fry are then gradually weaned onto a diet of Artemia nauplii over a period of weeks. Both these systems have definite advantages and disadvantages.

The main virtue of the easy method is its simplicity. Anyone who can incubate Artemia cysts can successfully use this technique, within its limitations.

Just set up an array of brine shrimp hatcheries, installing additional hatching containers to suit the number of fry you will feeding. Many commercially-made hatcheries are available or you can easily improvise your own from 2-liter soda pop bottles or quart jars. Fill the jars or bottles about 4/5 full with saltwater and equip each container with an airstone connected to a length of rigid airline tubing that reaches all the way to the bottom. An inexpensive vibrator air pump with a set of gang valves with put out enough air for the entire battery of hatching containers. Add 1/4-1/2 teaspoon of brine shrimp eggs to each container and adjust the valves so the airstones bubble vigorously, keeping the eggs in suspension at all times. Shine a light directly on the hatching bottles and keep them illuminated 24 hours a day.

The eggs will begin hatching after 18-24 hours, and the emerging nauplii should be harvested and used as soon as possible after incubation while they still retain their full nutritional value. (The yolk supply lasts about 1-2 days after hatching, and the food value of the nauplii deteriorates steadily as the yolk sac is consumed6. Once it has been exhausted after about 48 hours, the nutritional worth of the nauplii drops drastically.)

However, before they can be used as food, the nauplii must first be separated from the indigestible egg shells. Otherwise the empty shells may be accidentally ingested by the fry, resulting in intestinal blockages and death3.

The brine shrimp nauplii can be separated from the eggs simply by turning off the air for a few minutes and allowing the water to settle. The unhatched eggs will sink to the bottom of the hatching jar while the empty egg shells will float to the top. The nauplii can then be concentrated in the center of the jar by darkening the room and shining a flashlight on the jar’s midsection. (Brine shrimp are attracted to light and will be drawn together in midwater where the light is focused.) Harvest the nauplii by using a siphon or turkey baster to suck up the concentrated mass of shrimp. The shrimp-laden water can then be strained through a plankton screen or fine-meshed net.

Return the strained water to the hatching container, add more eggs, and readjust the aeration. The same hatching solution can be used for a week’s worth of hatchings before it has to be replaced.

Alternating the hatching container from which you harvest each day’s supply of nauplii will assure that you have a nonstop supply of newly-hatched brine shrimp available at all times. This is absolutely vital since a single 2-week old sea horse must consume a MINIMUM of 3,600 brine shrimp every 10 hours3. So much as one day without food results in severe stunting, and baby sea horses can starve to death in just a few days9.

Dr. Amanda Vincent, a leading expert on the courtship and breeding of sea horses around the world, recommends a feeding period of at least 14 hours a day11. In order to assure the fry are never left totally without nauplii, many researchers go one step further, and provide the young with constant light and food so they can eat continuously around the clock9.

The best eggs or cysts to use for your brine shrimp factory are decapsulated eggs which have had their hard, outer shells stripped away. These shell-less eggs have many advantages over ordinary Artemia cysts. For starters, they simplify the task of separating the live nauplii from the unhatched eggs, since there are no empty shells, and the decapsulated eggs eliminate the possibility of clogged intestines due to the indigestible cysts. Secondly, the decapsulation process destroys virtually all known pathogenic organisms. Since the shell-less eggs have been disinfected, there is much less risk of introducing disease or parasites to the aquarium when you feed your sea horses with brine shrimp from decapsulated cysts. More importantly, the nauplii produced from decapsulated eggs have greater caloric value than the nauplii from unaltered cysts. This is because the nauplii from decapsulated eggs do not have to waste energy struggling to break free of their shells, and thus emerge with 20% greater food value, primarily in the form of additional amino acids and essential fatty acids6. This extra nutritional value can make a crucial difference to the rapidly growing fry.

Decapsulated eggs are currently manufactured by New Technology under the brand name Artemia Revolution. Although the shell-less eggs are expensive to buy, it is possible for the serious hobbyist to decapsulate his own brine shrimp eggs at home.

This is done by soaking ordinary Artemia cysts in water for one hour to hydrate the eggs, using vigorous aeration to keep the eggs in continuous suspension8. The hard, dark brown outer shell (chorion) must then be dissolved away by suspending the hydrated eggs in a 50:50 solution of household bleach and tap water for approximately 7-10 minutes8. As the outer shell gradually dissolves, the eggs change color from brown to gray to white and finally to orange–the color of the nauplii within. The decapsulated eggs must be rinsed thoroughly to removed all traces of the bleach and used right away. If they are not to be used immediately, the shell-less eggs can be dehydrated by soaking them in a saturated salt solution for 3-4 hours8, keeping them suspended with heavy aeration during this time, after which they can be stored indefinitely.

Although an in-depth discussion of the decapsulation process is beyond the scope of this article, interested readers should consult the excellent article by Patrick Sorgeloos titled ”Decapsulation of Artemia cysts: a simple technique for the improvement of the use of brine shrimp in aquaculture,” which appeared in the September 1977 issue of Aquaculture (Volume 12, pages 311-315). In addition, detailed instructions for the decapsulation of Artemia cysts can also be found in the Plankton Culture Manual by Frank Hoff and Terry Snell, which is available through *Florida Aqua Farms (904-567-8540).

CAUTION: Be advised that the decapsulation process involves the use of harsh chemicals, and remember the reactions that dissolve the outer shell of the cysts produce considerable heat, particularly if a large amount of cysts are treated at one time. Before attempting this procedure on your own, be sure to consult the complete instructions in the references listed above, and follow all the necessary precautions to the letter.

It is intriguing to note that some crustacean larvae and fish larvae can be fed directly with decapsulated Artemia cysts, without hatching them first8. The shell-less eggs sink to the bottom, but if a system could be devised to keep the decapsulated cysts in suspension, perhaps by using mild aeration to gently swirl them through the water in a lifelike manner, it’s possible that sea horse fry would accept them as well. This would greatly simplify the task of sea horse rearing, and it represents a promising avenue for future research.

The easy method of sea horse rearing, in which the fry are raised on a diet consisting solely of newly-hatched brine shrimp, has been used successfully by the Steinhart Aquarium to raise Hippocampus erectus fry obtained from gravid males3. Kirk Strawn has also used this method to raise Dwarf Sea Horses (Hippocampus zosterae) through several successive generations9.

Although it can be an effective technique, which is simple and inexpensive enough for just about anyone to try, the easy rearing system does have its drawbacks. For example, it is only suitable for those species of sea horse which produce fry that are larger than about 0.4 inches or 1.0 cm in length (see table below). This includes Hippocampus erectus, H. fuscus, H. histrix, H. whitei, H. breviceps, H. comes, H. ingens, H. abdominalis, and *H. zosterae.

Fry of this size (greater than 1.0 cm) are large enough to eat newly-hatched brine shrimp for their first food,11 which makes them much easier to rear than most marine fishes. Fry that are significantly smaller than 1.0 cm cannot swallow baby brine shrimp, and can thus even starve to death when surrounded by swarms of nutritious nauplii.

The following table indicates the approximate number and size of the fry produced by various sea horse species10,11. It will give you a good idea which sea horses are best suited for the easy rearing method:

Species Number Size (cm)
H. abdominalis 300-600 0.9-1.5
H. erectus 100-800 0.8-1.3
H. fuscus 10-100 0.8-1.2
H. kuda 250-600 0.6-1.0
H. histrix 100-300 0.7-1.1
H. whitei 40-150 0.7-1.1
H. comes 150-500 0.6-1.0
H. breviceps 20-110 0.7-1.0
H. zostera* 5-70 0.6-0.8
H. reidi 300-1500 0.6-0.8

Notice that each spawn contains fry with a range of sizes. Many species produce some large young in each brood, which meet or exceed the crucial 1.0 cm mark, as swell as some small fry less than 1.0 cm which are too small to eat *Artemia nauplii as their first food. This makes culling by size an absolute must for the hobbyist who uses the easy rearing method. Runts are doomed under this system and must be ruthlessly eliminated in order to preserve only the largest fry for further rearing.

This generally means sacrificing a large portion of the spawn. The easy system will allow the average aquarist to raise a few fry from each brood to maturity5, but it typically results in relatively high mortality rates. It is a good choice for hobbyists who are primarily interested in raising replacement stock for specimens lost to old age and natural causes7.

The more complicated rearing system overcomes most of these shortcomings. It can be used for all sea horses regardless of how small their fry may be, it reduces the need to weed out undersized individuals, and it usually results in significantly higher survival rates. However, it requires greater expertise as well as a more substantial investment in time, money, and equipment, putting it beyond the reach of many aquarists.

The complex feeding system for sea horse fry proceeds in 3 main stages: (1) culturing microalgae as food for zooplankton; (2) culturing zooplankton (usually in the form of Branchionus rotifers) to use as the fry’s first food; and (3) gradually weaning the fry onto a diet of newly-hatched brine shrimp. The purpose of the first 2 steps is to provide undersized sea horse fry with small living prey (rotifers are 1/3 the size of brine shrimp nauplii) until they have grown large enough to accept Artemia nauplii as their staple diet. Once this is accomplished during the 3rd phase, feeding proceeds exactly as previously described for the easy rearing method.

The main advantages of this 3-stage system are that it allows the hobbyist to raise a greater proportion of each brood (the Berlin Aquarium regularly achieves an 85% survival rate when using this technique to raise sea horses11), and it can be used to rear all Hippocampines regardless of size.

Step 1: Culturing Marine Microalgae. Prepare culture medium by mixing 3/8 cup of aquarium salt to one gallon of sterilized, dechlorinated tap water, and then adding 3ml of Microalgae Grow per gallon of water13. (Microalgae Grow is an algae nutrient concentrate which can be obtained from *Florida Aqua Farms.)

Sterilize 2-liter soda pop bottles to be used as culture containers and obtain a starter culture of microalgae (also available from Florida Aqua Farms as Microalgae Disks). Chlorella is probably the most popular microalgae used in mariculture13, but Dunaliella also works extremely well and is preferred by Dr. Amanda Vincent11, an expert on the captive breeding of sea horses*.

Fill the sterile culture containers with culture medium and inoculate the bottles with algae cells from the Microalgae Disks according to instructions. Maintain the culture in constant light and aeration, placing the culture bottle(s) an inch or two from the light fixture (a pair of standard 48-inch fluorescent bulbs)13.

It takes a week or two for the culture to take hold and the algae to grow out into the ”greenwater” phase, so you must start your algae cultures growing weeks before the fry are born. When the culture bottles turn bright green, the algae is ready to be used as food for the zooplankton11.

It’s a good idea to start several algae cultures going at the same time so you can alternate which culture bottle you harvest the algae from each day. Whenever you use part of the ripe greenwater from a culture to feed your rotifers, be sure to leave 1/4 of the greenwater behind so you can restart the culture by refilling the bottle with fresh culture medium13. This will allow you to keep your algae cultures going indefinitely.

Step 2: Culturing Zooplanton (Branchionus rotifers). To culture zooplankton, set up 10-gallon all-glass aquaria filled with synthetic seawater. Adjust the salinity to match that of the nursery tanks and maintain the pH at 7.9 or below (room temperature is fine). Equip the culture tanks with airstones, add a quart of live rotifers to each aquarium, and give them 24 hours of light a day13.

Each day add enough greenwater from your algae bottles 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 sea horse fry13. 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.

Starting 24 hours after birth, sea horse fry should be fed continuously with live rotifers. Dr. Amanda Vincent recommends feeding 2 plankton nets of rotifers 5-7 times daily or whenever no plankton is visible in the nursery tanks11. In addition, she keeps a drip of diluted plankton (i.e., rotifers) going at the rate of 10 liters/day at all times. (A bucket of 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 valve11.)

Step 3: Switching to Artemia. After receiving plankton exclusively for 10 days to 2 weeks, the fry can be started on newly-hatched brine shrimp. Dr. Vincent advises starting with about 5 nauplii per sea horse per feeding, added to the fry’s usual feedings of rotifers11. After 3 weeks, gradually discontinue the rotifers and increase the amount of live brine shrimp until the sea horses are eating Artemia nauplii exclusively after their 4th week. (The weaning process works best with brine shrimp eggs from the San Francisco Bay area, since the nauplii that hatch from them are slightly smaller than the nauplii from other areas.)

By the time the fry are 1 month old, the complicated rearing system and the easy feeding method have ceased to differ, with the baby sea horses subsisting entirely on freshly-hatched brine shrimp in both cases. From this point on, the fry must have access to ample amounts of nauplii at all times, so continue feeding newly-hatched Artemia a minimum of 5-7 times daily until they are 6 weeks old.

By that age, the young should have nearly quadrupled in size11, reaching a length of about 4.0 cm or 1.5 inches, and they should no longer be treated as babies. Sea Horses older than 6 weeks have grown out of the fry stage and are now considered to be juveniles. It’s a natural cutoff point because Artemia nauplii are an adequate diet for the first 6 weeks of life, but after that age, such a diet becomes too imbalanced to support adequate growth*.

In order to thrive, juveniles older than 6 weeks require more substantial fare and more variety in their diet than they did as newborns, and the final segment in our series on sea horse nutrition will pick up where Part IV leaves off, focusing on the best foods for raising juvenile and subadult sea horses to maturity.

Author’s Note: The intricacies involved in culturing microalgae and rotifers are too complicated to cover adequately in this article. The basic information presented here is merely intended as an introduction to this subject. For more detailed instructions on these culture techniques, I refer the reader to the Plankton Culture Manual4 published by Florida Aqua Farms.

In addition, I highly recommend Joyce Wilkerson’s excellent article called ”Captive Food Chain,” which appeared in the Fall issue of *The Breeder’s Registry13 (Volume 3, Number 4: 1-4.) It describes a larval rearing system that would be ideal for raising sea horses, including step-by-step instructions for culturing microalgae, rotifers, and Artemia. (Joyce Wilkerson is available on CompuServe at: 70313,2435.)

If you are a beginner who is considering keeping sea horses for the first time, remember that breeding these fascinating fish is a painstaking, time-consuming process. In order to breed them, they must be given a healthy, balanced diet. That means collecting live foods in the field, maintaining live food cultures at home, patiently training them to eat nonliving prey and frozen foods, and even conditioning them to accept hand feeding. Rearing the fry requires culturing microalgae and zooplankton, and converting your bedroom into a veritable brine shrimp factory. A brutal feeding regimen and a strict cleaning schedule must be adhered to without fail. Nursery tanks must receive partial water changes twice daily. Anyone who is unwilling or unable to follow these rigorous routines should stick to less demanding fish more suitable for the novice.

If you decide you’re up to the task, be sure to make provisions for feeding and rearing your sea horses before you buy them. Sea Horses must NEVER be purchased on impulse! It’s vital that you line up live food sources or establish your own live food cultures before you bring them home. And keep in mind that it will be much easier to keep up with the bottomless appetites of these seagoing gluttons if limit yourself to a single pair and their progeny.

REFERENCES

(1) Bellomy, Mildred D. 1969. Encyclopedia of Sea Horses. T.F.H. Publications, Inc.: Neptune City, New Jersey.

(2) Giwojna, Pete. 1990. A Step-By-Step Book About Sea Horses. T.F.H. Publications, Inc.: Neptune City, New Jersey.

(3) Herald, E.S. and Rakowicz. 1951. Stable requirements for raising sea horses. Aquarium Journal 22: 234-242.

(4) Hoff, Frank F. and Snell, Terry W. 1987. Plankton Culture Manual. Florida Aqua Farms: Dade County, Florida.

(5) Keeley, D. 1980. Raising baby sea horses. Practical Fishkeeping. September 1980: 33.

(6) Selcon Concentrate User’s Guide. 1990. American Marine, Inc.: Ridgefield, Connecticut.

(7) Schmidt, Thierry. 1995. About sea horses. SeaScope (Winter 1995) 12: 2.

(8) Sorgeloos, P. et al. 1977. Decapsulation of Artemia cysts: a simple technique for the improvement of the use of brine shrimp in aquaculture. Aquaculture. Volume 12: 311-315.

(9) Strawn, Kirk. 1954. Keeping and breeding the dwarf sea horse. Aquarium Journal. Volume 25, Number 10: 215-218, 227-228.

(10) Vincent, A.C.J. 1990. Reproductive Ecology of Sea Horses. Ph.D. Thesis, University of Cambridge: 15, 61.

(11) Vincent, Amanda, PhD. 1995. Sea Horse keeping: feeding adults, mating, rearing the young, mariculture. The Breeder’s Registry. Volume 3, Number 2: 1-5.

(12) Vincent, Amanda, PhD. 1995. Update on sea horses. SeaScope (Summer ’95) 12: 4.

(13) Wilkerson, Joyce. 1995. Captive food chain. The Breeder’s Registry. Volume 3, Number 4: 1-4.

(14) Young, Forrest. 1991. Dynasty Marine Associates. 10603 7th Avenue, Gulf; Marathon, Florida 33050. (Personal communication).

Footnotes

*Florida Aqua Farms carries a complete line of products for use in mariculture. To order the Plankton Culture Manual or request a copy of their catalog, call 904-567-8540 or write: Forida Aqua Farms, Inc. 5532 Old St. Joe Road Dade City, Florida 33525

*Although Hippocampus zosterae fry are a bit smaller than 1.0 cm in length, they are better developed for their size than most sea horse fry, and are able to eat Artemia nauplii from the San Francisco Bay area as their initial diet, making them good candidates for the easy rearing method.

*Brine shrimp eggs from the San Francisco Bay area are the best for the easy rearing method, since they produce slightly smaller nauplii than brine shrimp eggs from other sources. These smaller Artemia nauplii can help fry of marginal size to survive the crucial first weeks of life.

*Microalgae Grow, Microalgae Disks starter cultures, plankton netting, and live rotifers can be purchased from Forida Aqua Farms. Phone 904-567-8540 or write to:

Florida Aqua Farms, Inc., 5532 Old St. Joe Road, Dade City, Florida 33525

*Dr. Vincent is currently working with Neil Garrick-Maidment to establish a central registry of serious sea horse keepers and a directory of breeding and rearing information in the U.K., in order to assist in sea horse conservation efforts.

Dedicated aquarists are encouraged to send their advice and suggestions on keeping sea horses to Neil Garrick-Maidment at the following address: Sea Horse Captive Breeding Coordinator 1 St. James Terrace Exeter Devon EX4 6HQ England

*The Wilhelmer Aquarium reports that young sea horses find Artemia difficult to digest, and no longer flourish on a strict diet of baby brine shrimp once they are six weeks old.

*The Breeder’s Registry is a central depository of information on propagating marine life. Its objectives are to encourage closed-sytem captive breeding of marine organisms in order to limit demands on wild populations, and to act as a registry for active breeders to acquire and exchange broodstock and increase gene pools.

To obtain a copy of Joyce Wilkerson’s ”Captive Food Chain” article or to request information on breeding and rearing sea horses in general, contact Stanley D. Brown at:

The Breeder’s Registry, P.O. Box 255373, Sacramento, California 95865-5373

Telephone: (916) 487-3752

E-mail address: [email protected]