Yes, I've seen the "short gut" reference as well.

I guess I don't really know what it means to have a short gut, because that picture has what looks like a long and complicated digestive tract. Maybe I'm just interpreting it wrong.

I did find scientific literature that says specifically that grass carp do not digest cellulose. Digestion of cellulose I believe involves use of specific types of bacteria, which the grass carp don't have.

So what does it mean to have a "short gut"?

Holding a redear sunfish is like running with scissors.