I currently have a ten-gallon tank that I am looking to fill with female bettas in a nice little sorority. I also currently have two female betta that live together with no squabbles whatsoever, which inspired me for the idea. I got them both from a petshop that keeps all their female bettas in a single tank, so they already had their pecking order set out. The problem is, I've heard many different numbers for an 'ideal' sorority in a ten-gallon tank. Currrently, my estimates are for five or even six girls in that ten-gallon tank. Five would be preferable, but I'm not sure. So, help out a thoroughly confused person? Five girls? Six? Or just four?