In the '70's-'80s I kept a dozen, dozen & a half perch snd smallmouth bass as groceries for my turtles. Problem was, I grew enamored with them, and then they'd be off the menu and treated like pets. They were tolerant of temps from the mid 50's to mid 80's and would eat anything from worms and smaller minnows to pellets. They'd leave medium goldfish alone, but beat up and eat the smaller guys.