any dog can fight with any dog. what breeds interest you. do you want a bigger or smaller dog, long or short hair, do you want a dog with am easy to antain coat, do yoj ant a girl pr boy.
you will have teathing problems just like wigh childeren who get a new baby brother or sister, o know someone who got a new puppy and it was months before the older one accepted the new pup, now they are the best of friedns.
my lot play with GSDs, staffies, dalmations, collies, terriers etc so it doent real mater what breed will get on it mor what you want. i kow people with cockapoos who have boxers, winmanaras, tibeten terriers, cocker spainals, labradoodals etc, get your self a beed book and have a look and see if any breed would fit in ur life stile better.
good luck.