With sororities its best to overstock and do more water changes than to understock. My sorority is a 10 gallon planted with 7 females. I do two small (25%) water changes a week and the fish are fine with that. Cycling is what is important... it allows you to have more females without jeopardizing water quality.
My sorority originally had 5 girls and they were fine. Its always better to have more females though because the aggression can be spread around.
Last edited by 1fish2fish; 08-11-2010 at 02:08 PM.