A dog fight that goes beyond a brief scuffle and doesn’t resolve quickly is frightening to behold. In fact it’s one of the behavior scenarios most likely to result in significant injury to humans, not to mention the dogs. The first, most important thing to remember is stay safe. After that, here are a few things to do to try to end the conflict as quickly as possible, with minimal bloodshed.
1) Spray me a river. Blast the dogs with water from a nearby hose, assuming a nearby hose with a powerful enough spray. An easily portable aversive, such as lemon juice in a spray bottle, can be an effective alternative. In a pinch, even a fire extinguisher makes a handy and effective fight stopping tool.
2) Sound strategies. Depending on the intensity of the fight, a loud yell might put it to rest. Try dropping one or several metal pans on the floor. A marine air horn can be effective at breaking up a fight. Warning, they are loud.
3) Keep your hands out of the danger zone by using a physical object to break up the fight. You have to plan in advance. This would be a good idea if you have two dogs that have shown a propensity to get into fights with each other. Attach two handles to a small piece of plywood. When the fight happens, lower the board between the sparring dogs. The board will push them apart.
I have been lucky and never had to break up a dog fight. I think that the biggest danger of a fight that most of us will encounter would be when walking our dogs. Carrying a hose just won’t work so a small air horn device, like the ones that some folks have a sporting events, is probably the best choice if one is worried about a fight.