if it is ick...i doubt it. my kole tang had ick and my shrimp didnt do jack. i had to quarantine him to a hospital tank. i had to do this b/c i have corals and inverts in my tank and the medicine could and more than likely hurt them. if u dont have any inverts or corals throw in Marcyn1 or 2. they come in pills. i also use ocean life "lifeguard" pills. just make sure you take out any carbon packs that you have in your filter b/c it will neutralize the medicine.
also, i would only treat the entire tank if more than one fish has the ick. if its just one fish your ganna want to quarantine it into another tank. b/c if it dies and other fish eat and pick at it especially your "cleanup crew" they will contract the ick then your starting all over again