I have a 1300 gallon pond. 10 feet long x 5 1/2 feet wide x 3 feet deep. There's a ledge that goes all around the pond and from that ledge to the water surface is about one foot. The pond is currently stocked with one 5 inch RTC, two 4 1/2 pangasius catfish, one 5 inch blue channel catfish, tons of guppies, and 5 or so goldfish. I just want an aquatic turtle that will live in the pond and not try to eat or nip at my fish. I don't really mind him eating my goldfish and some guppies but I don't want him nipping or eating my catfish. Anything out there that stays small?