Becca
Members
You might look up myxobolus cerebralis, which causes whirling disease. It is a parasite and there is one stage that does attach to the surface of the fish, which may be what you are seeing.
I do not believe there is a cure once the whirling starts. Don't know about before it starts.
Menhaden in the Chesapeake Bay get it sometimes. The organism is in all local waters.
Interesting. Some of the symptoms Christine's fish are having, including the really fast onset, are similar to what I saw in my fish when the 29 crashed. I did not, however, see any growths on their heads or bodies.