Noun

1. A tiny freshwater fish, Poecilia reticulata, popular in home aquariums, that usually has a plain body and black or dark blue tail for the females and a more colorful tail for the males.

   Fred kept a tank of guppies by the windowsill.

2. By extension, any tiny fish.

   Throw that one back; it’s just a guppy!

Scientific names

• Acanthocephalus guppii
• Acanthocephalus reticulatus
• Girardinus guppii
• Girardinus petersi
• Girardinus poeciloides
• Girardinus reticulatus
• Haridichthys reticulatus

• Heterandria guppyi
• Lebistes poecilioides
• Lebistes reticulatus
• Poecilia poeciloides
• Poecilia reticulata
• Poecilioides reticulatus