Your dog is going to interact with other dogs from time to time. This is why it’s important that every dog owner learn safe ways to break up a dog fight. Read full guide here: https://topdogtips.com/safe-ways-to-break-up-a-dog-fight/
If another dog is circling around your pet, or stalking him, this may indicate a potential attack. Raised hackles and tight lips are also signs of aggression. While these actions could also be signs of playing, it’s best to assume the worst before the situation gets out of control. Barking, growling, snapping, lunging – all of these things may be a clear intention of attack.
"Possibly the most success of all of the safe ways to break up a dog fight is known as the "wheelbarrow method." You can only use this method if there is another person with you. Both adults needs to grab the back legs of their respective dogs. Pull the dogs away from each other, which will make it impossible for them to keep fighting. Once they are separated, each person needs to turn in a circle and face their dog in the opposite direction."