Yellow Tango insano

[Gizmo]

I dont know what happened, but my yellow tang is flipping out attacking everyone in the tank. He's scratched the hell out of the foxface, the clowns hold their own, and everyone else ran for the hills and is hiding. Any reason this sort of behavior should occur? The foxface and tang have been co existing for about a month now, added within a week of each other. I'm at a loss.