Hello, this is Dr. Bruce and I would like to help you with your puppies.
It is actually quite normal for puppies to fight and wrestle. Sometimes it can appear to be very violent, even if they are only playing. Unless one of the dogs is trying to get away, and the other one keeps attacking, then you don't really have a problem to worry about.
I have seen many, many clients with puppies that are "fighting", when in reality the puppies are merely playing very roughly.
Certainly, if you want to reduce this activity, then it is necessary to try and offer them alternative play. Many toys, walks, treats and distractions will help, but will probably not eliminate completely the behavior you refer to.
The only time I worry is if there is a much bigger dog that will not leave the smaller dog alone, and the smaller dog is cowering and hiding.
I hope this helps. If you would like to continue this chat, please reply to this post and I will get back to you as soon as possible.