Ah I see. I'll observe his behavior before I put him in because I have 5 1" dats inside the tank. Also, the NGT is really lazy and stays at the bottom of the tank constantly.
btw... what kind of aro is it? many will say jars will turn on you after a certain size... i just keep an eye out for the guy. but generally you can keep them together. they are good tank mates with each other.