My oscar is one of my favorite fish who is unfortunately living in a bin right now. I'm getting a new tank tomorrow and I was wondering how large his tank mates ( if I add any) should be? He is a big softy and has never fought with any fish he has been with. If it can't fit in his mouth he never bothers it. Even fish he can eat he leaves alone for weeks until he decides to eat them. So how large should the tank mates be for an 11" oscar?