You can have some corals in a seahorse specific tank, I have mushrooms, sponge,gorgonians, xenia,zoos and Kenya trees in mine. These corals dont require halides or very much flow at all so they are fine with the seahorses. A tall tank is required and you can put small docile fish in there. I have chromis and gobies in mine just a few though because the seahorses eat very slow and would starve with faster fish around. Carrie