...for Marine Aquarium Cultured Fishes and Invertebrates

SEAHORSE KEEPING

(Part 1 of a 2 part article)

© Dr. Amanda Vincent
University of Oxford, England

Article by Dr. Amanda Vincent, Copyright 1995. Reproduced by permission.
(This article first appeared in Volume 3 Number 1, The Journal of MaquaCulture Winter 1995.)

Editor's note: Dr. Vincent kindly allowed Joyce Wilkerson to use excerpts from her "rough notes" for this article. This article is not to be reproduced without the permission of Dr. Amanda Vincent, Darwin Research Fellow, University of Oxford, Department of Zoology, South Parks Road, Oxford, OX1 3PS.

INTRODUCTORY NOTES

Seahorse keeping should not be tackled by the casual aquarist, because seahorses usually die quickly in captivity. Seahorses are already at risk around the world, partly because they are exploited for aquarium fishes. The following notes are intended only for very experienced marine aquarists. Think about whether you can realistically hope to care for these fishes, before you buy them, and if you have any doubts, choose something easier.

The Seahorse

Seahorses are in the same family as pipefishes and seadragons (Syngnathidae). There are probably about 35 seahorse species in the world, all in the genus Hippocampus, ranging in adult size from the 40 cm Eastern Pacific seahorse (H. ingens) to the 1.5 cm New Caledonia seahorse (H. bargibanti). Seahorses usually cling to vegetation or other holdfasts such as sponges, pilings or ropes on the bottom, sometimes in less than one meter of water and often only meters from shores. Crabs occasionally prey on seahorses. Seahorses can change colors often and easily. Do not distinguish between seahorses by color. The head coronet shape and size vary greatly from seahorse to seahorse and are an excellent way of identifying seahorses individually.

New Seahorses

Choose your seahorses with great care. If they have grey tinges or signs of fungus or sloughing skin, do not buy them. It is difficult to impossible to treat most seahorse illnesses. Seahorses in good condition have rounded bodies. If the body is sunken and concave it is probably best not to buy the animal, as it has obviously not been properly cared for and will almost certainly succumb to illness. Seahorses are very vulnerable to bacterial infections so place new seahorses in a separate tank which has been treated with a wide-spectrum antibiotic or dip them in a bath. To acclimate seahorses, the unopened plastic bag should be placed in the aquarium for about half an hour to allow water temperatures to equalize. Then gradually, over the next hour, add aquarium water to the bag. Once the bag is more than half full of aquarium water, you can risk adding the seahorse to the tank.

To encourage a seahorse to release a holdfast, move the holdfast gently. If that fails, then tickle its tail. As a last resort, try to uncurl the tall gently from the perch. Never use force to get a seahorse to release a holdfast. You will do great damage to its tail. Just wait and try again.

AQUARIUM INFORMATION

Seahorses are oriented vertically and are not suited to shallow aquaria (<45 cm). They are unlikely to mate in shallow water because they rise as they copulate. However, they often move across the tank bottom so give them as much space as possible. You should not keep many seahorses together. They do not live in groups in the wild and they are very prone to communicable diseases and ailments. I suggest no more than four seahorses in a 100 liter aquarium and not keeping any seahorses in much smaller tanks. An ultraviolet sterilizer is an important because seahorses are very vulnerable to bacterial infections. It's a good idea to hide airstones. Seahorses are subject to many buoyancy problems that may result from or be exaggerated by sitting in airstone bubbles. Water quality is all-important for maintaining seahorse health.

Aquarium Settings

Seahorses require many holdfasts, as they become stressed if they cannot hold onto something with their tails. The best holdfasts are natural surfaces such as "living rocks." Excellent substitutes are soft plastic plants. They should be quite tall and have many branching parts. It is also important to provide a reasonably complex environment so the seahorses can escape into hidden corners. They become stressed it they are too exposed. It's also a good idea to have a tank backing to give them a reference point and to help them orientate.

Companions

It's very important not to put seahorses in an aquarium with fast, agile fishes or with aggressive feeders. They tend to do best in invertebrate aquaria but otherwise they can be kept with dragonettes (Callionymus bairdi), tiny trunk fishes (Lactophrys trigonus), small pipefishes (although it has been suggested that these may become 'fin pickers'; as they grow), blennies, etc. Never place seahorses with active feeders such as damselfish, puffers, butterfly fish or angelfish. Blennies in particular make quite good companions because they help to keep the tank clean. Be careful that the companions aren't too large: one of my blennies which had grown large suddenly attacked all the seahorses in its aquarium one day, killing a number of them.

Lighting

Seahorses interact most in the hours just after dawn. I suggest, therefore, that you keep seahorses on 3 hours half-light / 10 hours light / 3 hours half-light / 8 hours dark. The half-light can be produced by a lamp some distance from the aquarium.

FEEDING ADULTS

Seahorses eat a great deal but are rather particular. Feeding seahorses is one of the most difficult aspects of keeping them in captivity. Seahorses usually eat only live, fresh food. They need food variety and cannot be fed solely on Artemia as these alone provide a highly unbalanced diet. With patience and effort, you may convince seahorses to eat some frozen foods and these can be a good backup when fresh food fails. However, you must not rely solely on frozen foods as these alone will eventually result in malnutrition and illness.

HEALTH

Seahorse are vulnerable to many fungal, bacterial and parasitic ailments and infestations and few seahorses ever recover from a serious illness. Seahorses should be inspected every day for changes in their health and any ailment treated immediately; one seahorse's illness usually hits all seahorses in the tank very quickly. Any ill seahorse should be isolated at once. If in doubt, I risk treating them with a wide-spectrum antibiotic.

Buoyancy problems are fairly specific to seahorses. Any seahorse staying constantly near the surface is almost certainly an ill seahorse. You should react at once as buoyancy problems are serious and often fatal. Again, prevention is better than cure. Try to ensure that you have no dissolved gases in your system (in contrast to suspended gases) as these appear to be a major trouble source. Symptoms are the following:

1. A grossly distended body - by then, the problem is far advanced (c)

2. Inflated pouch not due to pregnancy - avoid wishful thinking if the animal hasn't been near a female (a)

3. A constant head down position when swimming (a, b, c)

4. The tail curled well back and up behind the trunk (b)

5. Small bumps on body surface (b)

6. Tightly curled position (when trying to descend), held for an unusually long period with little progress (a, b, c)

7. Immediately bobbing to surface after release from holdfast (a, c)

8. Lying approximately horizontally at water surface, even if the tail is holding something (a, c)

The letter(s) in brackets refers to possible causes and solutions below.

a) Air trapped in the pouch (males). You can try the following to release the air. Do not lift the animal out of the water. Keep the seahorse underwater and massage the pouch gently. Hold the head upwards so the air can escape. Stretch the pouch between your thumb and forefinger. Manipulate gently and insert a hollow, blunt small-bore object (e.g. plastic tubing). Exert gentle pressure on the pouch. The gas may escape via the tube. Move the tube gently around if needed. You may need to suck on tube as you massage pouch (yuck!). Ensure that you get the air out. Then monitor that animal as buoyancy problems tend to reoccur in the same animals. This problem is especially prevalent around courtship periods and occurs if males dilate the pouch opening in air streams.

b) Air trapped under the skin is a more acute problem. Use a sterile syringe needle (with a tiny diameter). Slip it gently (at an angle) under the skin to pierce a small hole. Remove the needle and then massage the bubbles out while the animal is under water. Pierce all the bubbles you see because they are usually interconnected and missing once causes a repeat performance. Keep the animal in a very clean tank after puncturing the skin.

c) Air trapped internally is very serious and generally results in death. I am unable to suggest anything useful to do in this case. Try to detect this condition early on as it only worsens. Seahorses appear to have no solutions of their own and become very stressed by such buoyancy problems. Seahorses in this condition have massively bloated bodies and get several related problems such as sores, skin cracks, frayed and tattered tails, bony plate separation and internal injuries.

The following are problems common to many fishes and can be pronounced in seahorses:

Bacterial ailments result in greying body parts with ensuring skin sloughing and secondary ailments. Treatment does not seem to be effective and most animals die within days. A dip may help seahorses combat such illnesses. I have found that if bacterial infections do take hold, they are distressing and incurable. An ultraviolet sterilizer can be enormously helpful in combating bacterial infections.

Fungal infections are quite common. If any area develops a white "fuzzy" look and begins to look soft and spongy, treat for fungus. ISOLATE. See aquarium manuals for precise instructions. One possible method is to add malachite green to a treatment tank. Be warned, though, that seahorses can suffer ill effects from too much malachite green so remove the seahorse after a few days or change much of the water. Otherwise, you can dip the seahorse in more concentrated malachite green, or try swabbing the affected part with 1% malachite green. Be certain that you are using zinc free malachite green. Wear gloves because this stuff stains.

Parasites on seahorses are usually a Glugea microsporidian but other parasites may also afflict them. Most parasites appear initially as small, white dots on the seahorse and can be confused with the natural markings on the seahorse. Know your seahorses' markings well and check them regularly. Sometimes, if things have gone too far, the parasites clump into "cauliflower" or "wart" groups. One possible treatment is to place seahorses in a freshwater bath and then dip them in a formalin bath. You can also treat with copper sulphate. Follow instructions in a good manual. Seahorses surprisingly, need not be considered very delicate when treating their ailments and can be subjected to reasonably strong cures...

Wounds are not common in seahorses as they are very passive fishes. If something does happen, try to leave the wound alone. Many things solve themselves if left alone in a clean tank. Otherwise treat according to a good manual. Dilute iodine on seahorse wounds appears to cause more trouble than it solves.

Protozoan or crustacean infections happen in seahorses. If a seahorse is gasping, panting, or lethargic, it may be a protozoan infections or crustacean infestation in the gills. This can be treated by dipping in a freshwater bath and then in a formalin bath. You should see little white things fleeing from the respiratory spiracles/pores etc. on top of the head.

Finally, please be realistic about your chances of curing an ill seahorse. If a seahorse is deteriorating rapidly or suffering evidently, please do not insist that the animal dies slowly, and perhaps painfully. It is far better to make the decision and kill the animal quickly. If you can't do that, you should not be keeping seahorses.

SEAHORSE CAPTIVE BREEDING CO-ORDINATOR

Please send any of your own advice and suggestions on keeping seahorses to Neil Garrick-Maidment, Seahorse Captive Breeding Co-ordinator, 1 St James Terrace, Exeter, Devon EX4 6HQ, England. He is working with Dr. Vincent to establish a central register of serious seahorse keepers and a directory of breeding and rearing information, in order to assist in conservation efforts.

Part 2 of this article is available HERE

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