How do I know when my Guppy is Pregnant?

A pregnant female guppy will have a large or swollen abdomen. This is perfectly natural. She will give birth every 30 days and even without a male can give birth to up 6 times without further fertilization. With these fish you could ask yourself, when isn't my guppy pregnant? If you have a female guppy in your tank, chances are, she's pregnant!