If they've been in the same tank as a male, any time within the last six months, they will be pregnant (unless there's something wrong with them and they're infertile).
Yes; both those fish look pregnant. The black and white one is probably quite close; less than a week I would say. The yellow one, probably a couple of weeks away yet.
Thankyou, I've also got 2 other females that look pregnant but not too sure how far gone as I've only had them for a week as well, I'll upload a picture tomorrow
She is very very VERY close, probably in labor right now, get her in that breeding trap! I know because she has fully squared off and have you seen how open her backside is?! It's to let the fry out.