Why wouldn't the fish share his candy with the other fish?

Q: Why wouldn't the fish share his candy with the other fish?
A: Because the other fish ate him.

My nephew told me this. It is a pretty good joke in my opinion. The humor is the dissonance between what you expect the answer to be and what the answer actually turns out to be.

Fish that are considering sharing candy are probably talking animals, and therefore wouldn't be expected to eat each other. That they still do that is surprising.

This might be classified as black humor.