You can identify the male and female Molly fish by analyzing their body color, entire shape and size, and behaviors.
In addition, Dorsal fins and Anal fins, also play a significant role in identifying the male and female Molly fish.
*Male Mollies*
It is fairly easy to determine the sex of a male molly. The males have pointed Gonopodium i.e modified anal fins they use to mate with females. Dominant male mollies intensify in color and grow larger fins to produce a mating show for females or to show dominance to other males.
Female Mollies
Female mollies have bulky figures; they're wider than males at the rear of the abdomen for breeding purposes. When pregnant, she will take on a bulging, lumpy appearance. Her fins are shorter; the anal fins are triangular.
