The question here seems to be over your use of the words "viciously" and "aggressively".
Without actually being there, it's hard to judge exactly what level his behavior is and where it might be coming from because those words are sorta loaded and different people have different ideas about what that means. But I don't like to see any kind of bite from a pet dog toward his family...bruised and swollen does imply some force.
I would wonder if he had some pain or was startled somehow when you petted him and he bit you. Or if somehow when he was healing he experienced something painful when you handled him a certain way and that he's thinking it will happen again. That's the first thing I would think of.
Fixing him wasn't really likely to modify his behavior, especially if he's responding out of fear, but I don't know that doing it at the time you did actually caused his behavior, per se.
I guess what I would recommend is that you consult a behaviorist, someone who can maybe come to your house, to see his arousal level with your family and when you have visitors over. It's just tough for us to recommend anything on the internet...you need someone who is trained to actually see your dog's behavior in person to figure out where it might be coming from, and to give you an idea how to proceed from now on.
He's had a tough start and it may be more difficult to get him to a stable place, but I wouldn't necessarily jump to the conclusion that he has some kind of unfixable genetic or inborn problem which is causing his behavior. You just need to gather more information from someone who can actually put their eyeballs on the situation.
Without actually being there, it's hard to judge exactly what level his behavior is and where it might be coming from because those words are sorta loaded and different people have different ideas about what that means. But I don't like to see any kind of bite from a pet dog toward his family...bruised and swollen does imply some force.
I would wonder if he had some pain or was startled somehow when you petted him and he bit you. Or if somehow when he was healing he experienced something painful when you handled him a certain way and that he's thinking it will happen again. That's the first thing I would think of.
Fixing him wasn't really likely to modify his behavior, especially if he's responding out of fear, but I don't know that doing it at the time you did actually caused his behavior, per se.
I guess what I would recommend is that you consult a behaviorist, someone who can maybe come to your house, to see his arousal level with your family and when you have visitors over. It's just tough for us to recommend anything on the internet...you need someone who is trained to actually see your dog's behavior in person to figure out where it might be coming from, and to give you an idea how to proceed from now on.
He's had a tough start and it may be more difficult to get him to a stable place, but I wouldn't necessarily jump to the conclusion that he has some kind of unfixable genetic or inborn problem which is causing his behavior. You just need to gather more information from someone who can actually put their eyeballs on the situation.
