How do you tell if a guppie fish is pregnant?

It is very easy. Like all livebearers when the female is in pregnant it will develop a dark triangular shaped gravid spot near her anal vent. As the pregnancy progresses this dark triangular shaped gravid spot will get larger and darker.
The feemale will be getting bigger and bigger every dayand she also will havw a dark spot on her belly before her tail. She should be a girl, have a protruding belly and a small dark dot near the base of the tail.
She should be a girl, have a protruding belly and a small dark dot near the base of the tail.