Truthfully don't think that ANY of my fish would do that. I've kept some 1/2 shrimp in there with no consequence! But, just to be safe, it seemed like a 2 inch fish would be perfect. Especially because my leporinus is only supposed to get to be at most 7 inches, but some people say they will still try to eat smaller fishes, or grow to be a foot, but that is only specific types of leporinus. Must be specific fish though that will try to do that, because mine doesn't bother anyone, not even my 1 inch cockatoo cichlids. Although I think my little rosy barbs are going to have to go, because someone keeps trying to shred my angels fins, and I'm not sure who would do that, but they seem like a good culprit. Hmm... Maybe I'll just post a question on it. Oh, and I'm planning, depending on the size of the fish, to keep about 5-6 in there.