Hi Heather! Is he acting normal (eating well, no flashing, swimming normally)? Is he the only fish with this? Have you felt the lump (firm or soft/squishy)? Is there any discharge or anything else weird about it? I will be honest, I am not exactly positive what he has. The lumps are perfectly round which makes me wonder if its some type of odd parasite or just simply an unusual growth/tumor. I would qt him and observe him/the lump for any changes.