My sailfin tang at approx 5 PM 1/9 got sick...its colors went really dark and he just sat on the bottom breathing heavily. Those were the only signs. This morning he was still alive but this time with a "bug" on one of his fins. Is this a parasite and how do I treat it. Unfortunatly he has passed away by the time I posted this but I need to know how to fight these things since I am fairly new to this hobby. Thanks in advance!
Bug Pic Link
http://home.rochester.rr.com/netthis/P1110078.JPG
Bug Pic Link
http://home.rochester.rr.com/netthis/P1110078.JPG