Mollys with big bellies urgent !

[Billygeorgedear]

Hiya I'm brand new to this and I'm doing this on behalf of my mothers tank, she has 2 mollies of which I think they are or they might be platys but either way both there stomachs are massive, she has had a few over the course of some time and the all slowly dying off, these still seem to swim fine and don't see any signs of illness but there bellies are enlarged, I have checked and changed the water also as I have koi myself so tried to help her out with water changes incase of nitrates and immonia ect but I just don't know unless they are pregnant but how can both of them be ? I've attached some photos bellow thanks

 

[fluttermoth]

Those are guppies.

They probably are pregnant; most livebearers can store sperm for around six months, so can continue getting pregnant, even if there are no males in the tank.