I'm so sorry! Often times with fish, its almost always a guessing game when diagnosing. Could be anything between a tumor to a bacterial infection, I hope its nothing. Keep the thread updated, I really want to see where it goes. I'm very glad to hear he's still eating.Thanks! It is so weird! The betta is still doing great. He's spazzing out more. I think the swelling is blocking his vision a little. Still eating like a champ. Very active with the other fish. The lump doesn't look like it grew any. I was thinking maybe it was a heater burn or something? I don't think they get that hot tho. All I keep thinking when I see him is, Awee my poor duck looking fish :/.