How Do I Tell If My Molly Fish Is a Boy or a Girl?   Your Molly
fish will show secondary sex characteristics to tell whether it
i a boy or girl between 2 and 3 months of age. If it is a male
the fin closest to the tail will have a tubular shape while on
the female this fin will be fan shaped. The male is also more
elongated than the female who is rounder. Q&A Related to "How Do
I Tell If My Molly Fish Is a Boy or a..." males have a pointed
bottom fin females are more round. It's all in the anal fin (the
rear fin on the bottom just before the tail fin). In a male, it
will be skinny and pointed and separate from the body, in a
female it will fan out like as far as i know a female Mollie has
an even tail and a boy Mollie has thin parts like structure
suspended from its tail and the boy has a bigger fin on top and
a girl has a smaller Explore this Topic To tell if your betta
fish is a boy or a girl is by looking at their fins. A boy betta
has longer fins than the girl bettas do. Boys are also a little
larger in .