I've heard too many horror stories of dividers being jumped...and the glass dividers don't allow for proper filtration and heating. In a 10 gal 1 male or a sorority of females. You can do 4-6 females in a 10 gal..some say no less than 6 (I have 6). I've heard accounts of 2 or 3 females living together peacefully but I've also heard that you are far more likely to eventually have violence between the girls if not grouped in larger numbers. Sororities are awesome but require a lot of research and a heavily planted tank. Putting females with a male should only be done to breed and even then it can be a violent process. A female is just as likely, if not more likely, to kill your male than the other way around.