I have platy fish and would like to know how this particular fish look like when the female is pregnant?

They will have a rounded belly which will besquared like a box when due date is soon... she may also tend to hide behind plants or houses... if you have more than 1 platy then compare their sizes with the 1 your talking about and ull see if its fatter then its probably pregnant!

Also if her belly was getting fatter alog the days then she's probably pregnant and getting sooner to giving birth

What signs do I look for her ready to give birth