I’ve had PBT in a 90, 250, and 310 (all separate fish). While I’m sure you don’t want to hear it, the PBT was a total aggressor in the 90 (4ft long) and went after anything to show dominance. In the 250 (7ft long), he would have a spat or two occasionally with the angels or yellow tangs, but nothing serious and would do his own thing. In the 310 (8ft long), this PBT tends to actually hang out with the other tangs as they swim back and forth. Very little aggression from him if any at all (so far).