Seahorses in the Aquarium

The unmistakable appearance of the seahorse is one that has captured people’s imagination for centuries. These unique animals have had a range of magical qualities bestowed upon them from curing baldness to treating impotence! Sadly, wild populations have suffered as a result of this. There are now seahorse farms in NZ with breeding programs to supply this ‘medicinal’ market as well as the pet trade.

Despite appearances, the seahorse is actually a fish belonging to the same family as pipefish and the dramatic sea dragons. Seahorses have a highly unusual reproductive strategy where the male becomes pregnant and gives birth to the young. The female lays eggs directly into the male’s brood pouch where they develop over several weeks into tiny independent replicas of the adults.

Although I wouldn’t describe seahorses as ‘easy care’ they do make fascinating and beautiful aquarium pets. The species most commonly kept in NZ is the native Pot Bellied Seahorse, Hippocampus abdominalis. This species can grow up to 30cm long so an aquarium with a minimum volume of 20 gallons and a height of at least 45cm is best. A thin layer of coral sand or finely crushed shell is a good substrate. To recreate the seahorses’ marine environment, seawater can either be collected from a pollution free source or made up with a synthetic mix. Accessory heating is not necessary with the ideal temperature range between 18 -22 degrees Celsius. It may even be necessary to invest in an aquarium chiller to prevent overheating. Artificial coral is the best form of decoration and is a good way of providing essential ‘hitching posts’ for the seahorses to wrap their tails around. Allow at least ten days running in time for your aquarium before adding any livestock and use a filter start bioculture to create a healthy environment for your seahorses.

Maintaining water quality is vital to successful seahorse keeping. A canister style external power filter is best to achieve this along with a fortnightly water change of around one third of the water. Ammonia, nitrite and pH levels must all be monitored weekly with the aid of test kits as well as checking salinity. It may also be necessary to add special marine trace elements from time to time.

Correct feeding is equally important to water quality. Although it is now possible to buy frozen shrimp for seahorses they will not truly thrive on this diet alone. A variety of live food is essential for a long and healthy life in captivity. Any small crustacean will be eagerly sucked up in the seahorse’s straw like snout with an audible snap. Small shrimp and other tiny marine animals may be collected from rock pools and live daphnia and brine shrimp can either be purchased or raised at home. Seahorses should be fed twice daily, enough to be eaten within about five minutes. Uneaten food, particularly of the non living variety should be removed immediately as it quickly decomposes with a detrimental effect on water quality.

For the dedicated aquarist, seahorses will certainly add a little magic to the home!