I disagree with the turtles eating fish. I kept a yellow belly slider in with a Peasei Cichlid and Clown Loaches for quite some time. Couple points you need to make it work:
- Acquire the turtle young.
- NEVER feed live or dead fish. Once they acquire a taste for it...it's over. Feed shrimp, commercial diet, etc.
- Make sure you have enough sturdy hiding places for the fish.
- Vegetation/obstacles for the turtle to get around.
My turtle/fish relationship ended when the Pearsei beat up my slider. As a result, I gifted the turtle to a boy who had always wanted one. Sold the pearsei to an MFK'r shortly thereafter.
As for the clown loaches? When the turtle rested on the bottom the loaches would frequently pick at the turtles shell and steal food.
Is there a possibility they will eat the fish one day? Yes. Is it certain? No, absolutely not.