What does it mean if my fish opens his mouth wide?

Question

he just finished eatting the head of this fish and now theres another one in the tank. is it because hes stretching his mouth or is he burping or is he like choking? thx

Answer 1

I've seen all of my fish do that .  I always thought it was yawning.  It's nothing, my fish have never had any problems with sickness.

Answer 2

they are yawning, it is cool seeing catfish do it.

Answer 3

There is speculation that, just like with humans, it is little more than stretching, which is supported by the common accompaniment of flared fins.  Also, it might be an attempt to force the fish down its throat.

Answer 4

its looking for food around the tank, feed them when they use it