I bought a purple tang and when I introduced it in my tank middle of the night, I thought everything will be safe, but the next day to my horror, the yellow tang started attacking my purple tang. Worried, I caught the yellow tang and let it be in a plastic container which was kept floating for two days. Today, I decided to release the yellow tang back to the tank and was very worried that it may attack the purple tang but was glad to see that the yellow tang mind it's own business.....some how containing the most aggressive fish in a separate container while introducing the new ones...( same family) helps a lot... Thought of sharing my experience.....