[reefkeeper2]

Lately my Powder Blue Tang has been exhibiting odd behavior. Normally he swims about, nibbles on rocks, intimidates a few other fishes, i.e. normal king of the tank behavior. Now I see him racing about the tank, slashing at the aquarium walls, dashing to the surface. He eats mysis and other foods but no longer eats the nori. He looks great, but something is up.
The tank is 427gal with a wide variety of fish and coral. Any ideas whats got into him?