the easiest way to tell males from females is that males will be smaller, more colorful and will have longer finage. Females are usually much larger, will have short rounded fins, and are usually kind of drab. Females that are pregnant will have a dark gravid spot on their stomach. 2-3 females per males is a good ratio.
thanks alot guys, i picked em up yesturday 2 females and 1 male and theres a female thats already pregnant, apparently she was preganant when i got her thanks alot guys