Has he been fixed? If not that will do wonders for his aggressive behavior. However it may take a month or two to see much difference. I have a soon to be 3 year old Chocolate male and he was rowdy and chewed my wife up before we had him neutered. He still barks a good bit but he is a well behaved young man now!

"Politicians and diapers must be changed often, and for the same reason." Mark Twain