My one neon had a swollen section at the end of his body for awhile and he has been fine for months but today I noticed it looks like there is a zit on it. He swims fine and no other fish in the tank have/had it. Any idea what it is? treatment?
No other white spots just a fair sized yellow/white zit head looking thing and a little swelling on the other side of the tail. He has always been swollen for as long as I can remember. He swims and eats fine, no others have any spots or swelling.