When we brought Sherman home, I kept both dogs very close by me for several days so that I could moniter their behavior. I gave them both treats & praise, and made sure they both got petted at the same time. I also spent extra time individually with each of them, too. Star is very dominant, but fortunately Sherman is happy as the underdog, which was apparently his position in his original kennel. We have not had any problems. For several years I had two females, and it was pretty ok until female #2 grew up, then the nasty fights broke out. It was very distressing. After my other dog got hit by a car, I asked around alot and was told that probably getting male would be a good thing as dogs of opposite sexes fight less than two dogs of the same sex. That has been my experience, too. good luck.