There can be n number of reasons that can cause kids to start a fight between them. Usually, they are regarding sharing of toys, or riding the other’s bi-cycle, or eating a piece of other’s pudding or cake, and other little and innocent reasons, which only kids have. If your kids indulge in frequent fights and are always quarreling with each other, then there is definitely cause of concern. However, if the altercations are not that frequent, then I do not see any need to worry too much about.
It is also important that elders should usually distance themselves from such fights and let kids sort out things on their own. It is only when the issue gets physical and the matter comes down to exchanging blows that the parents can step in finally, and call a truce among kids. Moreover, it will also be wise to not side with anybody and remain neutral when such altercations take place between kids.