Dogs don't always get along with other dogs. Fights sometimes occur, both due to circumstances but much more often because a human wasn't paying attention. It's hard to know what to do when your dog is attacked by another dog - you might not be able to stop the fight (nor should you always interfere since it can be very dangerous), but there are things you can do to help your dog afterwards.
For us, it happened so quickly. I'd brought my happy dog out for a walk in the deep, soft snow - something he always loves - and we were on our way home from the off-leash park. I clipped him back onto his leash for the walk home through the neighborhood streets.
My dog had just bounced back to his feet from a playful snout-first romp in the snow, when out of the corner of my eyes I saw a blurry flash.
Then I heard a scream... a scream that came from my dog, who had been knocked down by two big dogs who seemed to appear out of nowhere to attack him.
Until it happens to you - although I hope it never does - you don't know how horrifying it is to hear your dog yelping and screaming in fear and pain. My dog is only about 30 pounds; a happy little guy who was minding his own business when he was attacked for absolutely no reason other than the fact that he was there.
I don't know how long the attack lasted. It was probably only a few minutes, but it seemed like forever. My mind was a jumbled mess of rage and fear, and it seemed like my dog's yelps of pain were piercing my brain and stabbing straight into my heart. I punched and kicked and yelled - but the dogs just kept coming.
The owner of the aggressive dogs finally heard the commotion and came running over. He tore his dogs away and chained them up at his house, which was across the street on the other side of a small park. Later on, he said that even though he knew his dogs were animal-aggressive, he didn't think anyone would be out walking in the snowy weather so he let the dogs loose outside!
My dog was lucky. He was shaking, but he didn't have any serious physical injuries. In fact, having the bouncy happy personality that he does, he was rolling in the snow in our yard about an hour after his attack. He yelped in pain at one point and stopped.
I took him to the vet who checked him over and gave him some antibiotics. My dog is pretty hairy so it's very hard to locate puncture wounds. When we got home I slowly and carefully checked him over and found 15 puncture wounds, two of which were quite bad. His right side was extremely sore.
The owners of the other dogs paid the vet bills in full. They admitted that it was their fault. At the same time, they also tried to persuade us not to file a complaint. We did anyways, and they were fined for allowing their dogs to run at large.
A dog attack can happen blindingly fast, so fast that initially your mind just can't comprehend what's actually happening. Trying to break up a dog fight generally isn't recommended since you can also get hurt... but there are a few things you can do to help diffuse the dog fight).
If you're unfortunate enough to have it happen to your own dog:
Dogs that are known to be aggressive should never be given the chance to exercise their aggressive tendencies. It is the owner's responsibility to keep these pets securely leashed and under control at all times. If it's your dog that's the aggressive one, work with a behaviorist to learn ways to safely manage your dog around others.
Hopefully you will never be in a position where you have to figure out what to do when your dog is attacked by another dog. Above all, stay calm. Keep yourself safe and get your dog the help he or she needs. Don't feel guilty about reporting the incident, no matter how apologetic the owners are or how nice they seem. You're doing your part in helping to keep everyone safe.