The smaller one mayn't but the larger ones do. The also grew fairly fast, a 40gal would be too small for one, and they spook very easy so you need a good size tank to have one.
Yeah, that's why I wrote too bad I only have a 40... I would probably risk buying one if it were from a fellow reef keeper and it has been in someone's tank for a while. But the chances of me finding a medium sized one from a fellow hobbyist are slim to none.