Your post brings another point to mind;
Obviously fish do not feel pain the way that we do....... Because if you bit into a Big Mac and a sharp metal object pierced completely through your cheek (ouch !!!) would you go on and eat it anyway ?
PETA gets mad when we stick sharp objects into a fishes mouth, but is it okay then, if the fish does this to itself ? Hmmm.

Anyway, I know that Bass will eat catfish, but I think they are way down on the list of choices, while trout are on the top of the list.
BTW, big catfish, especially Flatheads, will hammer smaller catfish, which is why they hate to get one in the farm ponds in the Southern US.
I guess the bottom line is, "big fish eat little fish" and the species of either is probably not too critical.

Peace,
Fish