thanks Hattie B I finally got thru to the search and found lots of info. I am 99.9% sure it is Lymphocyctis virus. My tank is only 6 weeks old and the fish have been placed in the display for about two weeks.
[purple tang, yellow tang. sailfin tang]
A little territory battle for the first 2 days, but all are friends now.
My point, maybe new tank stress. The fuzz seems to lessen every day.
thanks for your reply