While many aquarium hobbyists keep seahorses as pets, seahorses collected from the wild do not tend to fare well in a home aquarium. Seahorses will only feed on live foods such as brine shrimp.
Seahorses are prone to stress in an aquarium, which lowers their immune systems and exposes them to diseases.
In recent years, however, captive breeding of seahorses has become increasingly widespread. These seahorses tend to do much better in captivity and they are less likely to carry diseases. These seahorses will accept frozen foods such as mysid shrimp and they are not exposed to the shock and stress of being taken out of the wild and placed in a small aquarium.
Captive bred seahorses are more expensive, but are a better investment as they are much hardier and do not take a toll on wild populations. Seahorses should be kept in an aquarium to themselves. Seahorses are slow feeders and in an aquarium with fast, aggressive feeders, the seahorses will be edged out during feeding and starve. For this reason, they should be maintained by themselves and special care should be given to assure that all individuals obtain enough food during times of feeding.
Seahorses can happily co-exist with many shrimps and bottom-feeding animals however. fish from the Goby family are also good tank mates. Species to avoid completely are eels, tangs and triggerfish, squids, octopus and anenomes are especially dangerous to the slow-moving seahorse.