Also, YA, don't care about agressiveness. I bought them for eye candy. They are not stressed, or else they would all be wearing their 'stress stripes', correct? The females can be kept together if certain conditions are met : 1) No male Bettas are in sight, or any that closely resemble the male. 2) tank is nice and big 3) all females are young and same size, and all are released into the same tank at the same time. They are fine. The person who raised them did so in same hard water and pH that I have. They have Bettas over 4 years old that are still vibrant and healthy. To each their own, whatever works best for you, I guess.