There are many reasons that a dog might become aggressive toward other dogs. Some dogs might get nervous or fearful around other dogs. In other cases the dog is striving to be the dominant dog. And in other cases, the dog is becoming aggressive since he is defending his territory.
An owner can also be the reason why his dog is aggressive. This can happen because the owner never socially introduced his dog to other dogs or because the dog is trying to be protective of his master, or becomes aggressive in this way by becoming sexually aggressive too.
One way of stopping dog aggression is by making sure that your dog is socialized as a puppy to other animals. Puppies should be permitted to play with other dogs that are well behaved and mature.
This way, they will be able to learn proper dog behavior from adult animals. The puppy also learns that being with other dogs is okay and that he need not fight with another dog just so he can defend his territory or be protective of his owner from other animals.
When you see your dog become aggressive, you can stop dog aggression by immediately addressing the issue every time your dog does it. Never allow your dog think that this behavior is okay. You can opt to have the muzzle or the head collar only while the dog is in training to stop dog aggression but should not be the solution every time this type of problem happens.
Strict training is also one way to stop dog aggression so that the dog is tuned into the commands of the owner and not be focused on other animals. Remember that the attention of the dog is focused on the owner. This way, when the owner gives another instruction to the dog like sit or down, it would still comply regardless of the fact that there is another dog around.
You should also be able to control your behavior and emotions; no matter how small it is so that your dog will not get an anxious signal from the owner. This is also one way of helping your dog stop aggression as your dog will always take its cue from you.
Once the dog has been trained to focus, the dog can also be distracted by being trained to look for a treat when there is another dog around. The treat can be thrown to the ground and the dog can be told to find it, thus distracting the dog from the other dog and stop the dog aggression before it starts.