Don't think he got bit, I don't have any aggressive fish, other cory, tetras...very mild tempered. The water is ammonia 0, nitrite 0 and the nitrate is about 2-3...on the test card it shows colors from 0-5...it's on the upper end more toward 0. See where that little bump he has is on a white patch..that patch is on his other side also a little bit. Could it be some sort of fungus?