In my tank I had a platy (died a few weeks ago) and, amongst other fish, we also had a female swordtail. We were soon shocked to discover a lonesome fry, a cross between a platy and a swordtail. To conclude this rather pointless story: Platies breed easily so buy a few and they are more then likely to breed.How can i get two platies to breed? how do i know if i am buying a male n female or do petsmart or petco sell pregnant fish?