Is She Pregnant?

[Harlequins]

She'll drop when shes ready

 

[OldMan47]

In your situation, with lots of other fish, I would move her to a separate tank. A molly will drop 30 or so fry and you can expect most of them to survive if there is only the single female with them. If you have a drop of fry in a larger population, you may not see many fry survive at all. Although I do not like the breeder traps, a decent cover like this java moss in my guppy tank, is helpful for fry survival.