are my plattys pregnant

[vanilla]

hi we have 3 calico plattys 2 female and 1 male, the females have got very fat we think they could be pregnant but not sure. how long are they pregnant for?
what can we expect.
we have a 70 litre tank, guppies, mollies, sunburst platys, dwarf gourami, lemon tetra

 

[paige]

they can be pregnant for 4-7 weeks