I bought three pajama cardinalfish from a lfs that I found about a month ago, and one of them has a bubble next to its eye. Can anyone help identify what could be the cause? Do I need to treat him in my QT? The little guy is feisty toward the other pj’s, but that isn’t anything out of the ordinary. It’s eating well, and I’ve seen no signs of stress since I’ve had it, but I’m concerned about it’s eye. It’s already been treated at the lfs with Prazi and Copper. (Yes, I know I’ve got an algae issue on the back of the tank. I leave it for my clowns and my lawnmower blenny.)