I told u abercrombie, you would be shot down, now listen to me one more time, as I tell you, don't do it. It's basically impossible to keep them alive, and personally I think it's cruel to keep suck a beautiful and rare and big wild caught animal in such a small space. Most seahorses get alteast 8" long, thats pretty big, especaially in just a lil 15 or 20 gallon tank. It isn't as big of an aquarium as most people (Not in the fishy world) would think. Save your money, it's not worth the heartache of seeing such awesome looking creatures die. If you really want a saltwater tank, read those links I sent you last night, they'll give you a good start on what you need to know.