Update: Well, I added the yellow tang this evening to the 180. He has had a small bump on his nose, that I was worried about, so I had kept him in Qt longer. Once he was noticed by the other fish, my sailfin tang went after him. He took the abuse for approx. 2-3 min and jerked back towards the sailfin. After that, the sailfin showed submissive signs towards him. But right before the lights went out, the yellow tang had taken up residence in the center cave and was being territorial towards any fish he spotted around the entrance. Lights are out now, so I will have to see how they are tomorrow. And I will take some pics.