Guppy behaviour - Is this normal or is she sick?

I bought two guppies yesterday to add to my community tank. I have
never had guppies before. One is a male and one a female. Today the
female has been spending a lot of time resting on the bottom of the
tank. This seems ominous to me but perhaps it is something guppies
like to do? The rest of the time she swims around apparently normally.
The male has been swimming around near the top of the tank the whole
time.

Judy