for a pair thats a good size tank. I had mine in a 29. now there in my 55 with other fish. are these paired off? iif so thats fine, if not you will want to get several to sex and mate up . then take the excess back to the local fish store. I have/ had 5 but they were poops and 2 went by by, and there is going to be 2 more going soon if they do not stop harassing everything there ever bunk mated to.. the female is the meanest of them all.