I have two Hawaiian sailfin tangs in separate systems. The only form of vegetation that these guys don't devour is Halimeda. I had macros get into a frag tank, and I removed the frags in shifts into the tanks with the tangs. Bye bye macros. A 90's plenty big to house a tang, depending on tankmates. I usually use a magnet to keep the glas clean, but every so often I give them a treat and use a razor blade. They follow my hand to get at the little rolls that come off.