Okay, a happy update! Last night before I went to bed, I decided to try adding the girls in again. They started getting aggressive again, but I noticed that they were doing it toward the back of the tank. I had put a metallic blue background on the tank and I wonder if it was driving them nuts...I'm not sure whether it was the removal of the background or the fact that I just took them out and put them back in, but they're not fighting anymore and I'm really happy. Just a little bit of chasing once in a while. :)
And thanks so much for the PM Christina, I replied back.