Babies start squirting out
Seriously,, hundred's of folk's ask this question, and it really does not matter, unless you plan on interferring with what the fishes have been doing for eon's without our help.
Provide some floating plant's ,real or artificial for the fry to hide in,get some crushed flake food ready,and wait. Fish will do the rest.
Moving pregnant females, and trying to catch fry,stresses out the fish and large females bout ready to drop, will frequently abort the babies prematurely and they don't live long or are born with deformities.
Provide the floating cover, and more than a few fry will survive and that's all we need to do.
Those that think they gotta move the fish here ,there,plop it in breeder net, catch all the fry, really are not doing the fish any favor's.