It started as a spot at the side of the dorsal fin a few days ago- now it is a small growth. Could this be Lymphocystis? From what I read, it is not life threatening and usually resolves itself. Thank you for your input.
It could be Lymphocystis, but it's hard to tell without seeing it. My clown had it a while back and recovered completely. It ran it's course in about a week. I believe Lymphocystis is caused by a virus and not a fungus as Loule suggested.