What kind of "ich remover" did you put in the tank, exactly? I don't recommend adding meds to your main tank. They can often hurt inverts, LR, corals, etc. It's just not a good deal. The best way to treat ich is to put your tang in a QT and perform hyposalinity. Check out the FAQs thread at the top of the Disease and Treatment forum for more information on this. Also, the recommended tank size for Naso Tangs are at least 125 gallons. How long is your tank? :happyfish
-lefty