never with a fusco, but i have a venustus. my venustus is not agressive. hes the big guy in with a bunch of mbuna. he eats the fry, and feeder guppies if i want to feed him that, which i ussually dont. but he leaves the adult mbuna, 3-4.5" alone ussually. sometimes they piss him off and he takes a swing, but ussually he just chills. i know venustus are predators, but not to agressive as long as there arent females, at least ime. all fish are different, so who knows. but, guess that doesnt help much, as ive never had what youre looking for