college student w/ Pregnant Platy

Question
Hi, I have two platies and an african bullfrog. I noticed one platy was getting a little too fat yesterday (since she used to be the smallest in the tank) and on a hunch I looked up information on pregnant platys. Now I'm very certain she is pregnant but i don't know how long she has been. I was wondering how long the wait is until she drops. Also, the male has always sort of stalked her in the tank- i thought he was just bullying because she was so small, but now I'm worried it's because he's waiting for the fry meal. So i bought a separate tank for her today and now she's all set up with baby hide out plants and all that-  her gravid spot is recognizable but this is my first tank and i have no idea how dark it will get before she is ready to give birth. So the male is swimming around a 10 gallon by himself (plus the frog)and the female is in a 5 gallon by herself and I'm wondering if maybe i should put them back together until she is closer to her point- the problem is i don't know how long that will be. Is there any way to find out when she will give birth? The pet store employee explained that the fish cannot be on their own for long periods of time. Do you think they are ok by themselves at the present or should i put her back in the 10 gallon?
Thank you for your time!

Answer
Hi Gina,
  The pet store employee is completely wrong. She can be on her own indefinitely (that is a silly thing for the pet store person to say).

I would keep her in the 5 gallon until she gives birth.  It usually takes about 3 weeks but of course we don't know exactly when she started.  

-- Ron
  rcoleman@cichlidresearch.com
  Cichlid Research Home Page <http://cichlidresearch.com>