One big mistake people make when introducing dogs from different packs or bringing in new dogs is by just tossing them together in one pack’s territory and hoping that they’ll get along. Maybe they will and maybe they won’t. The best way to do that is introducing both dogs in a neutral territory, and the right place is the Great Outdoors!
In this way, you are allowing the dogs to first bond as a pack on the walk. Walk your dogs on leash for the first 15 minutes along the hike and then set them off leash while you are still walking. During and after the hike, dogs will bond smoothly and peacefully.
When you get back home to ones territory, make sure that the host and his dog enter their home first, and the visitors second. After they have bonded on the long walk, dogs will consider this as a grateful invitation. Make sure that there are no valuable possessions lying in the floor, it might be a trigger for a fight, so better to remove them at first.
If a fight happens it does not make it a disaster, but your reaction to it can. Even among the seemingly closest of pack mates, sometimes something can happen that will get them going at each other. Maybe a human member of the pack accidentally drops a high value food item on the floor and both dogs go for it. Things like that may happen.
The first step with the first fight is to break it up quickly and calmly. Focus on the dog with the higher level of intensity. Never yell or shout excitedly when breaking up a dog fight this will only elevate the aggression. You can use a loud grunt or shout like “HEY!!!" when you are close to them, but always in a calm manner. You’re not breaking up the dogs with your voice; you’re defusing the aggression with your energy.
The second and most IMPORTANT step in a dog fight is how you handle it after. The right way is to totally FORGET it happened, because your dogs will and they are good at it. The wrong way will be to start worrying about the next fight, because that is the quickest way to guarantee that it will happen again. REMEMBER, the worst thing you can do if you have dogs that fight is to ignore the problem by isolating them from each other.
Even the most seemingly balanced dog pack may occasionally have a fight. The important thing to remember is that you are in charge and conflict like this is not the end of the world. They may or may not fight again, but if worry over it does not become your obsession. If not, then you will NOT be feeding them negative energy that will lead to another fight. Reward them when they are being calm and submissive, and correct them when they are not.