Description: I have a 50 gallon tank with 3 South American cichlids (parrotfish). I recently introduced snails into the tank thinking it would help clean the glass, but it's not helping. Now I have one cichlid who has a large "bubble-looking" bump in the center of his forehead, about the size of a green pea and looks transparent. My pH is seriously off, so water cleaning is in order for this weekend. Has anyone seen a bump like this?