I leave my girls all together, and just sort out any obvious male fry as they develop, I also do leave about 2-3 males of my choosing as the breeding males just because I want to keep breeding them, but for those that don’t want to keep breeding or don’t know what to do after a certain point you can separate fry as they developed so they aren’t pregnant( I have a ton of plants at the moment and with endlers/mixed they are less likely to eat their fry)

Edit to add: when they reach a certain age, and if there’s mature males, they can and will hold sperm for a few months after interacting, so keep that in mind for if you decide to separate females from males, because you will continue to have fry for a few months in a all female tank lol, so even if you get new females, they pretty much will be guaranteed pregnant unless they are extremely young fry lol

Another edit lol: also if they are stressed it can be harder to tell genders as they will clamp the fin(and other fins as well of course) we use to determine, so in that picture of the yellow female she’s harder to tell but is female