I've had a yellow tang for prolly 5-6yrs now my friend had one that terrorized his whole tank,he ask me if I wanted it,with hesitation I said yes,figured my was peacefull and his agressive .I know how territorial they are .Well when I put him in my tank my tang beat the hell out of the aggresive bastard,,,,lol.I tried to catch the new one but he found a little spot that the other one or I could get into.The beating continued for a week or so,I thought he was done .Well after a while the new one would come out and stand up for himself ,fins and sides all torn up.Now they swim side by side like buddies.So the moral of the story is ,,,,,,,they are very hardy IMO,and a good choice.I have 6 different species of tangs in my set up and they keep my tank spotless of algea.