How long before a guppy can give birth?

Guppies mature and gain breeding ability at 3 to 5 months. They breed readily, reproducing every 1 to 2 months in good conditions, but frequent breeding lowers resistance and shortens life, so avoid it.

Litter size relates to body size: larger guppies drop 80 to 120 eggs per birth, smaller ones 20 to 50.