Mate had a dog exact same, small black pat, wanted to take on the world, attacked every other male dog within seeing distance....guy i bought him from just couldn't handle him!
I took him home, let him settle in in his own pen, next couple of days let him run about with muzzle on!
then over the next few days introduced him to the rest of the dogs, with muzzle of course, every time he launched an attack he got nailed by both the dogs and me!!!! And i mean a really good message sent home, the only alpha round here is me!!!!!
Continued this for the next few weeks, every now and again removing