Last month, while trying to stop another dog from going after my newf, I was bitten pretty badly on the forearm. I did what any loving pet owner would do: I tried to get in between the dogs and block them from one another. As a newf owner, I know to take the space of my big dog when I need her to listen. I stepped in front of her and the other dog, going in for the attack, latched on to my arm. In retrospect, I would never do this again.
So hopefully, you can learn from my mistakes. I present to you:
Ten things to do if your dog gets into a dog fight:
1) DO NOT, under pain of death, try to get between the dogs. You have a high chance of getting bitten. Trust me on this.
2) Citronella spray by the dog's nose
3) try an air horn. It can startle the dogs enough to pull them away from one another
4) spray the dogs with a hose. Or use a bucket of water
5) scream with a high-pitched screech. This can sometimes distract the dogs long enough to get them separated
6) carry a container of pepper spray
7) fire extinguisher sprayed to the dogs (make sure it is safe to spray in the face)
8) use a leash to "lasso" the dog's leg, and pull them out and secure to a tree/fence, etc. Then get the other dog by the back legs "wheel barrow-" style.
9) if the fight takes place inside, you can try slamming something to the floor to startle them
10) Try throwing a blanket over one of the dogs in order to confuse it
There is something else I've heard, but it seems ridiculous. Apparently, you are supposed to stick your thumb up the dog's bum. This startles enough to get the dog to let go. Now, I cannot begin to tell you how crazy this seems. If you get close enough to do this, you are probably going to get bitten.
The best way to stop a dog fight is to prevent it in the first place. Make sure your dog is dog-friendly. If you are at a dog park, monitor the play, and if they get too frenzied, bring your dog over for a break. Dogs that get too riled up can turn to aggression as their excitement increases. This is what happened to me with the dog my dog was playing with.