My friend had one and he was a very fun fish to watch! Left all the others alone for the most part. I do remember he had a molly in there for a while, but it was in bad shape. Watching him hunt the molly was really interesting! He'd go all inverted and swim backwards, watching it like a hawk.sick! i'm getting one for my 125. how do you like him? how's the hunting behavior? does he really bother the other fish? finally, what do you feed him?