http://lmgtfy.com/?q=seahorse+care">Check out this link</a>
[QUOTE=]There are very few tank mates that are suitable for a seahorse tank. In fact, most seahorse tanks are kept as Genius or Family only tanks. Most corals are not good for a seahorse tank due to the seahorse being scale-less and therefore prone to injury buy the stinging cells of the polyps. There are some gorgonians as well as soft corals that are seahorse safe. Most fish are not "seahorse safe." Seahorses are very slow and thoughtful eaters, taking a long time to pick out that one perfect morsel before snicking it up. Also, seahorses themselves would make a good meal for many common fishes (anglers, rockfish, and Tetraodontids). And the last group of animals that should be avoided are crustaceans, not only for the seahorses safety but for the safety of the crustacean as well. Seahorses are quite fierce predators and some of the larger species can snick apart cleaner shrimp and even smaller hermit crabs! Of course there are some species of crustaceans that pose a threat to seahorses themselves (larger crabs, and some of the more ferocious shrimps).
Instead of discussing further what cannot go into a tank to make a seahorse friendly environment, lets move on to what can be put in the tank. Of course, just about anyone would want a clean up crew, since seahorses can be quite messy eaters. Just about any gastropod (snails and limpets especially) can be put into a seahorse tank. I will suggest that you get several Nassarius snails if you are not going to have a feeding tray (also to be discussed later). There are some nudibranchs and mini-stars that could do well in a seahorse only tank. As far as fish companions go, just about any goby or blenny will be docile enough to live with a seahorse. Also, some clownfish and tangs have been known to do well in a seahorse tank, as long as they are well fed and a more docile specimen of the species. Of course, most sygnathids of similar size can be housed together. However, there is one exception to the rule. The Giant Pacific Seahorse ( H. ingens ) does not do well with other seahorses (or a tank that formerly housed other seahorses). This is the only species of seahorse found in the east Pacific, which makes H. ingens very susceptible to disease that other seahorses may carry.[/QUOTE]