The smallest STs were placed in the tank first. A few weeks later, after they had established territories, I put the CT, who was larger, in the tank. Because she was a 'foreigner', she didn't attack the other girls. And since she was larger, they didn't attack her. If you have some large or aggressive females, try to add them at least a few days after the smaller ones are added. smile.gif
In a tank with many hiding places and heavy filtration, minor nips should heal almost before you notice them. Having a slightly stronger current than normal will deter aggression. I generally have 2 HOB filters in my 10g.
I would have no more than 6 females in a 10g, and that's only with heavy filtration. You would probably be better having them in a 15g or a 20g (long, if possible).