Aggressive towards others
My dog Max used to be a quiet and scared puppy who would not go near strangers, and always be nice and play with people we put him around. As he got older (and this could have been from him being in the house more often) He has become very aggressive to anyone, all ages, who wasn't his immediate family. If he even sees someone else outside he will bark at them, and If they come even somewhat close he will try to bite them. He does this with other animals too, besides our other dog Co co. Its strange, because he is very sweet and playful with everyone in the house. Is there anything I can do, I don't want him to bite someone, and I want people to not be scared if they are a guest in the house, and I really just want him to be happy and controlled, and comfortable with others.