The achilles tang is the last fish you'll add - very aggressive fish and also an ich magnet! Mine had ich and went away on its own. Naso tangs are peaceful and yes, they can grow fast! I have 2 other big naso tangs in my 450gal - very cool fish. Every tank should have one IMO. You can check out some of the tangs (and angels) on my build thread.Which of the four would you say is the most aggressive? Achilles Tangs are quite expensive, but like that they seem to be smaller than Naso's.
