help!!

hi I am new to this forum but I need some advise.

I Have had two male russian white hamsters (brothers) for over a year now. I have had no problems apart from one being greedy and getting fatter than the other one!

however today the two hamsters were fighting each other very viciously they both have red raw bellys from scratching at each other and one has a cut on his face. We have separated them and going to take them to the vet in the morning. They have never done this before and don't know why they started can anyone help I am very worried