^^^ NO. Dude, a pit and small dogs cant live together, they kill them by nature. Get rid of one of them.
Its a pitt mutt what did you expect? Pitt mutts and pitt bulls KILL other dogs. Its bred into them, you can't train it out. You have to get rid of one A shock collar will only make your pitt mutt more agressive
Get rid of one of them or keep them apart. A shock collar will only make him obey when you are there. He will learn quickly that it is all right to attack when you aren't there.
Buy a shock collar and shock him when ever he seems like he's going to attack. And if he does pull them apart, flick the pit bulls nose, and put him in a cage.