First, never put yourself at risk. It's instinct to jump into the fray, grabbing the other dog or sticking your hands near their mouth. But even your own dog won't recognize friend versus foe in the heat of the moment. You could suffer serious injuries as a result and still not break up the fight.
Sometimes, two dogs cannot live together after fighting. This doesn't necessarily mean you need to rehome them, but it does mean keeping them separated for the rest of their lives. As we discussed above, you'd need to crate and rotate (using either literal crates or rooms) or split your house into two parts.
Limit Rough Play
It's great if your dogs play properly together. But don't let things escalate to the point where a fight might occur. Don't let one dog mount another or get too rough pinning another. Even chase games can escalate when one dog reaches the other.
If your dog does get into a real fight, do not attempt to separate the dogs by grabbing a collar or using any part of your body. You will likely get bitten. There are safer ways to break them up. A loud noise might distract the dogs.
Punishment should be avoided. The dog-dog relationship will not be improved if you scold, punish or hold down a dog as punishment; in fact you may make it worse by punishing the dog for signaling and communicating their aggressive intentions.
Some have recommended that the dogs not be anywhere near one another for at least 48 hours following the fight, even if they live in the same household, while others recommend that getting a positive interaction between the two animals as soon as possible is the best course of action -- at the end of the day, however, ...
A method that's sometimes successful is to open a long automatic umbrella between two fighting dogs. You just need to make sure it's long enough so that your hands stay far away from the dogs' mouths. You might also try placing objects like chairs or laundry baskets on top of the dogs to help separate them.
Just like human siblings, dogs sharing a household will frequently fight over resources like toys, food, treats, or cuddles from their favourite people. Hormonal changes might also be the culprits to fighting – this is especially true if they are of the same sex and one of them is sexually maturing.
Unfortunately, some fighting dogs will not stop fighting until an injury occurs that results in one dog backing off. However, some triggers are easily identified and can be avoided. Multiple dogs of the same sex that live in the same house (all female or all male) may be at a higher risk of fighting.
Once dogs have fought, you must separate them immediately and as calmly as possible. Do not punish them, raise your voice, and do not try to make them get along.
Many common behavioral concerns, including fear, anxiety, and frustration-related behaviors, become more evident at social maturity and can underly an overly aggressive response. The younger dog may be initiating confrontations to gain access to resources, though that is just one possible trigger.
In short, the answer is yes, a dog can be traumatised after a dog attack.
They can also become depressed after a traumatic injury or an attack from another animal.
Grudges with other dogs
To them, that other dog = bad news, even if they don't remember exactly why. Your dog isn't actively “holding a grudge” against that other pooch, but they are responding to the negative association that was formed the first time, and strengthened every time since.
The most obvious sign of a serious dog fight is if either or both animals are biting each other. This is an extremely dangerous situation, as an animal can be seriously hurt if they're not separated in time. Dogs fight each other. If you see your dogs engaging in this behavior, it's essential to act quickly and calmly.
Fortunately, there is a way out of this dilemma. If your dog attacks other dogs, or just really doesn't like other dogs, the good news is that new dog training techniques are being developed that can help you change your dog's association and aggressive response to other dogs.
Some dogs simply cannot abide other dogs and are happier being the “only child”. This is not the fault of the dog, only a special consideration that makes a dog unique. All dogs have their own personalities, and some are more amenable to canine interaction than others.
Introduce on neutral territory.
At first, walk the dogs at a distance where they can see each other but are not too provoked by each other's presence. If the dogs are not showing any negative behaviors, reward them with treats just for seeing each other.