If you have more than one dog, sooner or later they’ll probably have a falling-out. This can take the form of a minor confrontation during which one of them will give ground without any actual fighting, or it might involve one of them snarling and snapping. In some cases, their conflict can escalate into a full-blown fight. There is plenty of good information available on how to break up a dog fight, So I’m going to focus on prevention and preparedness. Hopefully, I can help you to recognize when your dogs are building up to a fight and head it off beforehand; and to be ready if one does occur.
You should keep in mind is that if your dogs do have a fight, that is not a reflection on you as an owner. Dogs are complex animals with full emotional lives and communication skills. They can easily get on each other’s nerves. The good news is that they generally communicate their tension in advance of any real confrontations. You can often tell if your dogs are heading for a confrontation by being aware of their body language.
Watch your dogs interact with each other. If one of them is stiff and tense, giving the other dog a hard stare, holding his tail stiffly, possibly holding his head lower than his shoulders, those are aggressive signs. His face may also be tense with a wrinkled forehead. He may also be wagging his tail in a short, stiff motion instead of his usual relaxed wag. These are signs of a confrontation that you need to head off before it escalates. The question is how to do this without endangering yourself or unintentionally triggering a fight.
If you think your dogs are getting aggressive to the point that a fight may erupt, the first thing to do is interrupt them. Do this by putting yourself off to one side and calling them in a relaxed, happy way. Don’t yell at them or make noises that would increase their excitement, just call them as if you want to take them for a walk or play with them. Above all, don’t just grab at one of them and try to pull him away. Depending on their arousal and stress level, physical contact could be the last straw that puts them over their behavioral threshold. The key is to present yourself as relaxed and happy, which will help to reduce stress and antagonism on their part. Once you’ve interrupted them, follow up with some play or petting for a few minutes, or even leash them up and take them for a walk. You want to completely change their mood. And walking a pair of dogs together is one of the best ways to reinforce socialization between them. Don’t offer them any food or toys until they calm down and relax.
There are things you can do to reduce the risk of conflict between your dogs. First off, forget any advice regarding “alpha dog” behavior or “pack mentality”. Do not try to identify a hierarchy among your dogs and do not try to reinforce one. They don’t exist. Dog’s aren’t pack animals and don’t have an alpha. If you try to create that kind of relationship with your dogs, you’ll only create conflict between you and them, and among them.
Second, set them up for success. Arrange things to avoid potential sources of conflict among them. For example, establish feeding times and place their bowls so that they aren’t eating in each other’s line of sight. One way to do this would be to feed each dog in his own crate, or by putting their bowls around different sides of a kitchen counter. Free-feeding can work very nicely in a single-dog household, but it is a potential source of conflict when more than one dog is sharing the space where food is present. Also, pick up their bowls when the meal is over. This reduces the possibility of guarding behavior between them.
Third, watch for signs of resource guarding. This occurs when a dog “claims” something and acts aggressively towards dogs or humans who approach it. This can happen with a favorite toy, a bed, or even a person; and when it happens it should be addressed early. With the right resources, a dog owner can address this problem and prevent it from becoming serious. Jean Donaldson wrote an excellent short book on the subject, titled Mine! A Practical Guide to Resource Guarding in Dogs. However, if the problem persists, or if the dog exhibits actual aggressive behavior as part of resource guarding, a qualified canine behavior professional should be consulted.
Lastly, watch your dogs when they play. If one of them begins to get over-excited, his play biting and wrestling can escalate into something more serious. Alternatively, if one of them gets tired and stops playing, the other dog may start getting on his nerves. So look for signs of either over-excitement or of one dog wanting to stop playing for a while.
The fact is that even a very good dog can have a bad day and forget his manners, or he could be a little bit grumpy with his housemate, so a fight can break out. This is no different than having human children in a house – the difference being that dogs will use their teeth. Again, there are plenty of good sources of advice on breaking up a fight once it starts and I suggest that all dog owners be familiar with them.  However, dog owners need to be prepared to implement that advice.
Knowing that fights can break out in a multi-dog household, there are certain materials that owners of multiple dogs should keep on hand:
First, if your dogs regularly play in your yard, keep a hose with a spray nozzle connected to your outside tap. Experts advise owners to spray fighting dogs with a strong jet of water, but that advice is wasted if you don’t have a ready source of water on hand.
Second, a loud sound maker ready at hand. This can be a whistle, or an air horn, anything that can startle and interrupt them.
Third, have a can of citronella spray on hand. This can be sprayed on the face and mouth of a dog that is grabbing and biting another one.
Fourth, have a barrier ready to put between the dogs and keep them separated. This can be a board or baby gate, or anything that gets in their way.
You can also keep a blanket handy to throw over a pair of fighting dogs. However, while this can work, it can also prevent you from trying any other method of stopping the fight.
And, lastly, keep a canine first-aid kit on hand. Have the your vets’ contact information ready, as well as the phone number and location of the nearest emergency veterinary clinic for any bite punctures or serious injuries to one of your dogs. Puncture wounds and lacerations resulting from a fight can be worse than they initially appear, are prone to infection, and should be treated by a vet.
An isolated fight among your dogs generally isn’t any cause for concern. They rarely result in actual injuries. However, if your dogs repeatedly fight or if a fight results in injuries to one or both dogs, then they should be kept separated from each other until you have consulted a canine behavior professional. Your veterinarian may be able to recommend a behaviorist, and qualified professionals in your area can be found on the websites of bother the International Association of Animal Behavior Consultants, www.iaabc.org , or the Association of Professional Dog Trainers. www.apdt.com .
 Coren, S. (2014). How to Speak Dog. New York, NY: Atria
 Kane, G. (January 19, 2019) AKC. Watch for Warning Signs of an Aggressive Dog. Retrieved from https://www.akc.org/expert-advice/training/warning-signs-aggressive-dog-fight-bite-barking/
 Tufts. September 17, 2021. Your Dog. The Myth of the “Alpha Dog”. Retrieved from https://www.tuftsyourdog.com/dogtrainingandbehavior/the-myth-of-the-alpha-dog/
 Gibeault, S. (November 9, 2023). AKC. How to Break up a Dog Fight. Retrieved from https://www.akc.org/expert-advice/training/stopping-dog-fight-confrontation-fighting-dogs/
 Madson, C. (August 6, 2023). Preventive Vet. How to BreakUp a Dog Fight Safely. Retrieved from https://www.preventivevet.com/dogs/how-to-break-up-a-dog-fight
 ASPCA Pro. (nd). How to Make a Pet First Aid Kit. Retrieved from https://www.aspcapro.org/resource/how-make-pet-first-aid-kit