Female Sisters

We had gotten the 2 sisters spayed about 2 weeks or so ago, and we watching t.v and they started to fight, I am not sure if they were fighting my male cat, but when we told our son to break it up he couldn't, so we had to get into the fight ourselves and I was bitten and scratched and my husband was bitten or scratched. So we have to get them back into the cages.... And they are still growling, my male is afraid to walk over the area the fight was and we had to cover the females; they were trying to fight between the cages.

Help!!!!!!!!!!!!!

Is this the first fight? Were they close? i suspect something triggered the aggression. Is there anything new around the house? 

This link http://www.thecatsite.com/a/breaking-up-cat-fights  may not only help you when or if another fight happens but it may give you clues as to the reason for the "skirmish".