Livebearers have lots of babies. As long as there is plenty of hiding places (plant cover and such) I have found no real need to remove them to have babies. Some may get eaten, but again, hiding spots will let some survive.
I have had platies crap out lots of babies. Mollies too. Hundreds at a time. If you're not careful, you'll be overrun fast.
Another thing is, livebearers are sometimes inbred. This is a risk with having a lot in the same tank. A few generations in and you'll find they stop because they become infertile. They also suffer genetic issues and have short lives.
The platies I had in one tank quite a while back now had that appearance. Turns out, blood worms are not the best thing to feed these fish. Any fish really unless you have a good quality blood worm. They had digestive blockages and died. They looked just like the picture here. It's hard to tell. They get gravid like thag when they are brewin up kiddos too. You'll know soon enough. Keep your eyes peeled for a bunch of tiny little fishies! They will hide all the time, so you may not see them until they are about 4mm long or so. If it is gravid, you'll have more fish that you know soon enough.
No need to remove them unless you have aggressive predators in there like tetras and stuff. They might eat the fry. Keep everyone fed and you shouldn't have any issues.
