Summarize:

If one of your dogs is uncomfortable, it will stare intensely at the other dog. The other dog may either return the stare, or lose interest. If both dogs are locked in an intense stare, be aware that tensions may be rising. To prevent a fight, you may want to separate the dogs. Certain dog movements--such as pulling their lips back, holding their head high or low, or baring their teeth—are meant to communicate a warning. If your dogs are acting this way towards one another, it may be best to separate them. If your dogs are making low, rumbly growls at one another, this can also indicate a warning. However, growls can sometimes be misleading. Look for the dogs’ body language and other behaviors whenever you notice a growl. If it seems like they might be posturing to fight, it is best to separate them.  All dog growls will sound a little different. It is important to listen to your dog and get a sense of the way it vocalizes. when necessary. If your dogs do manage to get into a physical brawl, you may need to intervene to prevent injury. Try some methods that can be done from a distance, in order to best prevent yourself from getting hurt. Some strategies include:  Make a loud noise. Spray them with water. Use a barrier to split them up (such as a piece of wood). Throw a blanket over them. Mild aggression between dogs can usually be handled at home. However, aggression can quickly become dangerous and even deadly. If your dogs cannot seem to get along, do not hesitate to call a professional.
Watch the eyes. Recognize the dogs’ posture and body language. Listen to the growls. , when necessary. Consult with an experienced animal behaviorist or trainer.