All that is needed is a male guppy in with her.
A guppy fish is pregnant for about 4 weeks.
The Gravid female will have the dark "gravid spot" in front of her vent. I can however assure you that if there has been a male in the same tank with a female guppy for any reasonable length of time she will be gravid.
Guppy fish are pregnant for about 4 weeks before giving birth to their babies.
The female guppy will develop a dark spot on the side of her belly during pregnancy. As the pregnancy progresses, the spot will grow darker.
The female gets a deeper tummy and there is a dark (gravid) spot by her anal fin.
Guppy fish are pregnant for about 4 weeks before giving birth.
A female guppy is pregnant for about 4 weeks before giving birth to live young.
No.
With a guppy you need to look at the gravid spot. This is a dark spot in the fish's belly. A large gravid spot indicates the fish is likely to be pregnant. You can tell how pregnant the fish is by how large the spot is. Sorry I have no experience with other species.
A guppy fish is a live bearing fish, but the female generally does not take care of her young, and will eat them.
No, unless a) the female fish got pregnant before the male died, or b) you buy a new male guppy and put him in with the female.
Female guppies are larger and plainer. The male is distinctive for his long, flowing, colourful tail and generally brilliant colours.