I got a smaller yellow tang yesterday to add to my 55 gallon. He looked great when I first put him in. But, apparently my atlantic blue tang didn't like him too much. After about 15 minutes, the blue started badgering him a bit. (The yellow one is about 2-3" and the blue is about 3-4".) I figured they just needed to figure out what the pecking order was going to be. Then I saw the blue nipping at the fins of the yellow. Every now and then, the yellow would turn to fight back a little, so I thought I'd see what happened overnight. I had the lights out in the tank since about 6:00 pm last night, and late last night they seemed okay.

This morning, though, the yellow's dorsal and tail fins are pretty nipped up. I put him down in the sump. What can I do?

I thought that since the yellow and blue were from different genuses (Zebrasoma vs. Acanthurus, respectively), they should be okay together. Or, is a 55 gallon just too small for 2 tangs?

BTW, I rearrannged all of my rockwork on Thursday.