One of my dogs loves to eat catfish heads and will pick the skeleton clean. She is always dragging up big old catfish & deer carcass parts. I don't know where she gets them. (She may even fish for the catfish in the creeks & swamps. But, the deer could be dog or yote kills)
I have a resident osprey on the canal behind my house. I often see it catch fish, but its nest is somewhere else, so I never see the "end" results.
Wading birds like cranes and herons will go after turtles as well as fish.
In your neck of the woods, I'd go with a coon but there's a few other critters that'll feast on a catfish and a turtle....