How long have they been in the tank for? Also are either of them pregnant, as this could cause one or both females to become very protective
If you only have a few plants in your tank, it would be wise to get a few more, or a hidey-hole for the angry females to retreat to, somewhere to get away from the other. I have a low growth plant with big leaves that my new additions seem to use for hiding under after they have been added to the tank, helps to relieve anxiety, which can also be a cause of aggression
If any fin nipping has occurred, you can use melafix to repair the damage, but I don't think it will come to any real harm
