I had a yellow tang, powder blue, and blonde nasso. the yellow was most dominant. usually the most dominant will corner the weaker tang and pick at him. just keep an eye and make sure it doesnt get to to bad. after a few days they wont even notice one another. the thing you have to watch with the yellow tang, that white spot is a razor sharp barb, and he will slash the others with it. he could slice them good, or even cause an infection which also isnt good. but my yellow was dominant, and after 2 or 3 days forgot all about the other two. and the blonde and powder blue never faught. another thing to remember is they feed basically the same, so competition for food source comes into play, once the dominant sees they will still eat, and the new tang doesnt affect his food supply, they shouldnt fight. I did put 2 seperate sea weed clips in my tank though. that seemed tohelp.