Join Date: Oct 2010
Location: Victoria, Australia
I never rearranged any of my sororities or removed the existing females. I would just throw in some pellets for any females in the tank to eat up the front, and then let the newcomer out at the back. Usually everyone was too full and too lazy to do much chasing or fighting after that.
If the newcomer was particularly antagonistic I would just chuck them in a breeders' net and hang it in the tank for a week. Seemed to cure 99% of over-aggression in my females.