Definitely post your water specs but if everything is normal, with Oscars everything can be perfect and they'll still behave like this sometimes. In humans is called personality, maybe we can call this fishyality??
He's probably just bored.
Some live food might help, not a lot or a habit but as a treat (after the appropriate quarrantine). If he's big enough, toss in a small cat or two for him to "play" with. JUST KIDDING!!! I would never give my Oscars just ordinary cats.... again, JUST KIDDING.
In Deland, there is a place on 17-92 (across from Bondeson auto dealership) that sells crayfish for $0.49/ea. They call em fresh water lobsters for fun, but my O's love 'em. It actually gives them something to chase. Just make sure your rocks are secure 'cause they'll really go after them.