J/K Put something in there that is too big for him to swallow. It will give him a chance to chase it around.Who knows,maybe he will get lucky and catch it.I put a big Flowerhorn in with my Black Wolf.I really got to see the aggressive side of him come out.
Touch his face with your hand then see if you want more aggression
Wolves are like any other fish, their temperaments vary. They are usually aggressive towards other fish but not many (mala's at least) have the glass banging attributes most of us are fond of. If that's what you want then get a Dovii
He has agression whenever he wants have you really check out his teeth. So when he decides to be nasty whatever is in his path most likely will be destroyed.