The seahorses look like a true Franken-fish. They have horselike heads, are encased in armor, have eyes that move independently in a way reminiscent of a chameleon, they have a prehensile tail similar to that of a monkey, and the males have a kangaroolike pouch. They are such odd fish, that early naturalists classified them as insects and mollusks. Fortunately for those that love these odd fish, captive-raised seahorses are readily available. Hippocampus kuda, the smooth seahorse, is one of a handful of species that is being bred in captivity and sold through websites and aquarium stores.
Difficulty: It is much easier than ever to keep seahorses because better livestock is available, and much more is known about how to keep them successfully. But seahorses are not for everyone. The first thing you need to do to ensure success with seahorses is to acquire a captive-raised individual or pair. Secondly, make sure that the seahorses get enough to eat and watch for signs of potential health issues. Feeding the smooth seahorse can be achieved by using frozen mysid shrimp, which can be soaked in a vitamin supplement. (There is also a bottled form of Mysis shrimp available now that is easy to feed, but it must be refrigerated.) Food must be presented in a way so that the smooth seahorse can readily find and consume enough food to keep healthy (most die as a result of being underfed). Feeding smooth seahorses can easily be done by introducing the food into a small, glass dish on the aquarium bottom. You can then use a turkey baster to direct thawed mysid shrimp into the dish. The smooth seahorse will quickly learn that this is their food trough and will pick the food items from it. Uneaten food can also be easily removed. This brings up another important seahorse requirement — they should be fed at least three times (and preferably five) times a day.
Physical description: Hippocampus kuda is a smooth species (hence the common name) with low spines on the body and a low coronet (crown) on its head. The smooth seahorse is often pale yellow to orange-yellow with small black spots. A dark brown to black color form, with pale spots and mottling, is also known. The color of Hippocampus kuda is variable and can change in captivity depending on its surroundings and its mood.
Range: The smooth seahorse is a resident of the Indian Ocean and western Pacific. The smooth seahorse is often found in seagrass beds or among sponges and debris on open sand flats and slopes (it typically is not found on well-developed coral reefs). The known depth range for Hippocampus kuda is a few feet of water to over 120 feet.
Compatibility: The smooth seahorse does best when housed in a species-specific aquarium. The smooth seahorse can have problems getting enough to eat if it is housed with more voracious feeders. If you insist on keeping the smooth seahorse with other fish, stick with equally methodical predators, such as small cardinalfish, gobies and dragonets. Snails, seahares and small sea stars (Fromia spp.) are invertebrates that do well with the smooth seahorse. Avoid placing stony corals, crabs and larger sea stars in the smooth seahorse aquarium.
Aquarium conditions: The smooth seahorse aquarium needs to be a quiet, safe environment. Water flow and aeration are important, but the smooth seahorse should not be exposed to direct, strong streams of water. Instead, a gentle to moderate dispersed flow is optimal. There must be plenty of hitching posts for the resting smooth seahorse to curl its tail around — these can be faux corals, live gorgonians or macroalgae (e.g., Caulerpa spp.). Make sure heaters are covered or in an external sump so that the smooth seahorse does not get burned, and do not leave filter intakes exposed, otherwise the smooth seahorse may get sucked up against it. Keep the smooth seahorse at a pH range of 8.0 to 8.3, a specific gravity of 1.021 to 1.024 and a temperature of 72 to 78 degrees Fahrenheit.
Care considerations: The smooth seahorse typically succumbs to gas bubble disease, which can be an external or an internal form. Gas bubble disease is easily treated with Diamox, which you can only get with a prescription from your veterinarian. Bacterial infections are also potential smooth seahorse killers — Vibrio is a bacterial infection that typically occurs when the smooth seahorse has suffered an injury.
Breeding: Smooth seahorses readily reproduce in captivity. The female smooth seahorse deposits her eggs in the male smooth seahorse’s pouch, where the eggs develop and hatch. The newly hatched fry are then expelled into the aquarium. The newly hatched smooth seahorses can be fed enriched baby brine shrimp or rotifers.