Bro don't think that way! Predator fish also eat live fishes why does he needs predatory fish he likes fishes like that? We can feed predatory fishes omnivore diet or frozen right? Its Its same as he said that he wants predatory fishes so instead i suggested him fighter fish which will fight till death and i by that i didn't mean let one of them die its common sense when the fight gets serious remove the one at disadvantage ! And keep it in another tank till it heals thats what i do i have done it a dozen of times and both fishes survived but yeah at last my oscar ate them that happened after 1 year of bringing them