My female platy didn't "square off" as such but she did look very fat. On new year's day spotted a single fry which already with its colours so must have been 2-3 weeks old I'm guessing. Mum looked very fat 12 days later but overnight she looked amazingly slim and this time I managed to see quite a few tiny fry. She was voracious tho and gobbled them up if she could catch them. Dad was the "maternal" one! I haven't separated mine as guy at LFS said I'd need a new tank every month if I did so I'm going the natural route and have imported a huge plant for the fry to hide in and they'll have to do what nature teaches them and hide or be eaten. Sounds callous I know but I haven't the room for any more tanks to be honest. It's great fun tho watching them develop!
Let us know how yours gets on!
Let us know how yours gets on!