If you're a dog owner with multiple dogs in the house, you know that they will inevitably fight. This doesn't have to imply any deep enmity. Animals are after all animals and there will be outbursts of temper. Of course, there may be deep enmity between two dogs and then it's always dangerous to let them into the same room together.
The situation is much more complex if you have multiple dogs. I once stayed in a house with 10 dogs and when they started to fight, it required many people to break it up. Most of the time, the fight is so fast and furious that you can't get close enough without being accidentally bitten.
However, if there are just two dogs, then what you can do is to pounce on the stronger one and with a heavy heave, pull them off the weaker one. If you do this early in the fight, there is a chance that the stronger dog wouldn't have got his teeth into the weaker one. Don't lift the dog off the ground, as this will tempt the other dog to bite the lifted dog where he or she can't defend themselves - or you lift them up so high that they can't be reached.
Sometimes, you can bring out something that your dogs are afraid of like a stick (provided they are afraid of it) and this breaks up the fight. Generally anything that can distract their attention.