First of all that little pup needs more love and care and also you should take advice from a good trainer. My friend was having a pet and it was too very aggressive. She tried a lot to maintain him and had made many attempts to keep him calm down but all was in vain, then she asked for the advice of a trainer in Rochester NY for dog training and she told me later that she is satisfied with the results. So you can too ask for the good guidance for your dog.