There maybe some wrestling or snapping of there jaws to show aggression. But from my experience it never ends in any damage.
I had 4 from 5-8" and 3 of them schooled very closely like alot of barracuda's. But one of them was a loner and he took a portion of the tank as his territory. And would make a dash at anyone that came close. But never would get close enough to make contact.
I still have the aggressive one after 4.5yrs and he is still the same. He is housed with 2 scombs, 2 hujeta's, and 1 charax gibbus. And he still owns the same corner of the tank.
So it all depends on the fish to whether you will see any aggression or not. But even in the worse situation I think the damage would not be more than a scratch. IMO