i have one male and one female molly in a small tank. i know that the female is pregnant but i'm not sure when she is going to give birth. the male molly is chasing her around and keeps putting his mouth where her poop comes out, and where i'm assuming the babies will come out. i know i need to separate the fries once they're born so they dont get eaten, but will the male eat them as she's giving birth to them? and how do i know when she's about to give birth?

Welcome to the Box!

When the female gives birth I would separate the fry into a breeding net/box or remove the female. Once they have gained some size x2+ their birth size they should be ok if there are only mollies in the tank if not it may be best to wait till they get bigger. Their growth rate will be determined by feeding mainly so just keep an eye how big they are at birth.

the mom will look like she swalllowed a pingpong ball before she gives birth you can buy a breeder box, its a box with a seperater that the babies can fall into and be safe from the mom after shes done take her out and leave the fry in the breeder box for a while till they get bigger. you will want to put her in the breeder box no more than 1 or 2 days before birth which can be tricky becuase no one knows when she will pop. So put her in at night then during the day let her swim around and just keep an eye on her

Just some reference pics of mollys that are about to birth. Notice on the second pic the white knot at her "back end".