Hi, thanks for your reply. I don't have a vet that would know anything about afcs so that's out. I can't tell if the bulge on the frog's side is hard or soft because it won't let me touch it. Now he is having a hard time staying on the bottom. He floats to the top unless he goes in his hides or stays near the filter. Could this be a internal bacterial infection and could I try using Marycin 2? Thanks.