my jardini is a discriminate killer. he picks his favorites and leaves them alone while he kills the others. he has killed plecos, cichlids, Oscars... right now his buddy is a little tilapia. I bought a bunch and threw them in there and he killed or chased them all except this one. I like this pairing because the tilapia eats all his leftovers. he keeps the tank bottom pretty spotless. my jardini can't get to all the leftover bloodworms for example, the tilapia takes care of all of that.