I'm with Esshup, don't think that fish was dead, its to bloody to have been dead for very long.
The Bald Eagles do that to my bigger catfish, they cant fly off with them so they drag them out on the banks and consume what they can eat right there.
I have a game camera set up by my automatic feeder and have some pretty neat pictures of them doing it, coming out of the pond, dragging the fish right over the camera.
