One of my bettas has a growth on his chin. It's a little to the left side of his mouth and is a little underneath the mouth as well. It looks something like a blister you would find on your skin, with a sac full of clearish stuff. Some kind of infection, I guess...but I couldn't find its description in my Maracyn pamphlet. His eyes and lips are normal size, so I don't think he has popeye or cottonmouth. The betta is active and eating. He shares a tank (and routinely flares with) another betta, who is fine. Should I just treat normally with Maracyn II?