That looks like early lymphocystis. It may get much worse, and there really isn't anything you can do other than keep the water clean and hope for the best. It could also be a malignant growth of some sort.
In all honesty, the fish looks to be in very poor health, even with the prolapsed rectum resolved. I don't mean to sound discouraging, but it sounds like you really care about the fish, and I wouldn't want to see it suffer. I'm pretty sure it has hole in the head disease, and there may be numerous other problems going on internally.
How old did you tell me this fish was?
I've very surprised that the prolapse corrected itself. I've never seen one that severe before.
Kim
In all honesty, the fish looks to be in very poor health, even with the prolapsed rectum resolved. I don't mean to sound discouraging, but it sounds like you really care about the fish, and I wouldn't want to see it suffer. I'm pretty sure it has hole in the head disease, and there may be numerous other problems going on internally.
How old did you tell me this fish was?
I've very surprised that the prolapse corrected itself. I've never seen one that severe before.
Kim