PlanetCatfish.com

Today as I was looking at my green Armored Cory I noticed that when he eats the floating flakes I sometimes feed him, they will go into his mouth and out a slit on one of his cheeks. I'm very worried, this catfish was rescued from a very dirty tank, is it possible its skin got openings from the poor water and he can now no longer eat? He seems to be growing very big and seems very healthy, but like I said, all his food is going out of these slits, they aren't noticeable until I really looked at him and noticed that this wasnt right. What should I do?

This is nothing to worry about. The flakes are probably too big, so when the fish eats them, whatever that doesn't get swallowed would go out the gill slits (the openings at the sides of the head).

Yes this is common with large food particles and Corys. Try some tablet food that it can nibble on.