i had two RES 8" and 9". They were kept with a large mouth, two dempseys, two parrot fish, and a red terror..... i always set a minnow trap and then drop in VERY LARGE creek chubs and crawdads..... the turtles never bothered my fish but would chase the chubs all over the tank until they finally wore them down and then would eat them.... same with the crayfish..... keep them well fed and you should have no problems.. the turtles make the tank very interesting and appealing to guests