My boys are 14 months apart, so I know how you feel with that one. Although, my boys didn't start fighting though until they were twice their age.
I use a parenting technique called Love and Logic. It's awesome and a fun way to parent. I would get the book from a local library or look at bookstores or look at www.loveandlogic.com to purchase.
There are several small things that I do when my boys start to argue. But then, they are used to my love and logic ways now, so I don't have to 'spell it out to them' anymore. What I would use is an 'energy drain'. They'll eventually understand that when mom has an energy drain (which you actually do! lol), then it's chore time for them or whatever they come up with to help you get your energy back. When they fight, you'll say something like "I think I feel an energy drain coming on. Your fighting is draining my energy." (Be sincere. No yelling. Very important.) Then if they continue, you'll interupt and ask them how they are going to help you get your energy back that they've drained from all of their fighting. Make them think of what they need to do. They need to help do YOUR CHORES, not theirs. This is explained further in the book.
Another thing I say to my boys are "I'm not listening to this for free!" They know that they'll have to pay me, which they absolutely don't want to do. The payment is with money or toys...my pick!
Also, if they have that much energy to fight, they have that much energy to do chores. So, do the energy drain a lot and if they start fighting...after a while when you say (you are actually giving a warning, so to speak), "I think I feel an energy drain coming on." They'll more than likely stop fighting at the moment, because by then, they'll know what it means when mommy is having an energy drain.
There is so much more and scenarios...dialogue actually. It's great! If you get the CD's...they are comedy! I love the "Helicopters, Drill Sergeants, and Consultants". (You are to become a consultant parent.) I hope this helps!