If your guppy is alive, and female chances are she IS pregnant. The gavid spot is a small dark area just forward and above the anal fin. This dark coloration is do to the eyes of the developing fry inside her.
Danio's are egg scatters and are not fertilized internally so your danio couldnt be pregnant. But if you have a female with a swollen, deep belly, chances are she's full of eggs. Breeding danio's is not difficult but it will require a seperate tank.