Prevent a dog fight before it happens by learning the "4P Warning Signs":
Posture: A dog’s body language can communicate fear, hostility or submission. Learn to read and respond to your own dog’s body language, and others.
Packing: More than two or three dogs packed together can lead to trouble. Break it up before it starts by leading your dog to a neutral area at least 30 feet away.
Possession: Whether it’s you, a ball, or a treat, most dogs will protect what is theirs. Remain aware.
Provoking: If your dog is continuously annoying another dog or dogs, or provoking attention, it’s time to leave the park.