kept a scopas tang (same family) for 2+ years in my 30g and if you read my post earlier in the week, i recently brought him to the LFS for a better home...he became a little too big for the 30, and far too aggressive, i couldnt add anything after him because he would kill it right away, i had smaller fish in the tank, but because they were there first, he was fine. it was supposed to be a temp. move but turned out to be ALOT longer....don't do it it will be a bad idea in the future.