Guppy Pregnancy

Question
I am new in the fish world and just bought two small spotted angelfish(a boy and girl) and two fancy guppies(one boy and one girl also). I have a few questions about my female guppy.
1)How do I know if my guppy is pregnant?
2)If she is pregnant do I need to separate her from my other fish?
3)What is a good temperature for my tank to be at when my guppy is pregnant?
4)My male guppy keeps going underneath my female guppy's belly and looks like he's smelling her..why is that?
Thank you very much!!!  

Answer
Hi Amanda,
The guppy when she is pregnant will have a very large belly and a (dark) gravid spot. You do need to seperate her from your other fish but since you dont know when your last dropping is you can't mover until the birth starts. Then your supposed to wait like 20 days and put her in another tank for a week for another dropping (just for future occasions im telling you this.) A good temperature would be about 78 degrees f. The male going under the female his him mating with her by storing packets of sperm in her.
        Samantha