Well, in the stickies it says that some fish you can feed him are the litte minnows(look it up in the stickies under what to feed yout turt; feeder fish) and guppies but stay away from any kind of goldfish(not good for them). You can find them in your nearest pet shops. Just look for small, fast, and skinny little fishies
You don't need to feed the little fishies becuz:
1. they feed off algae and crud
2. don't waste your money on a whole bottle of flakes and when you try to feed the fish, your turt will eat the flakes or the fish won't eat all the food and the water will get dirty.
3. The fish will die anyway and/or will get eaten by your turt.

(I always feel bad for the cute little fishies)