TankBud

Variety of Guppy

Grass guppy

Poecilia reticulata

One of 9 varieties of Poecilia reticulata · See all varieties →

Also known as Pink Grass Guppy, Blue Grass Guppy

FreshwaterBrackishFish

Grass guppy (Poecilia reticulata)

Varieties · Poecilia reticulata

See all 9 →

Care at a glance

Temperature
64–82°F
18–28°C
pH
6.8–7.8
Adult size
2.4 in
6 cm
Minimum tank
13 gal
50 L
Temperament
Peaceful
Social behavior
Social
Swim level
Middle
Difficulty
Beginner
Breeding
Easy
Rarity
Very common
Family
Poeciliidae

Overview

Grass is a tail pattern: fine dark speckling scattered across the caudal and usually repeated in the dorsal. Shops sell it by base color, most often Blue Grass, with Red Grass and Pink Grass on the same plan. Two looks circulate under one name: solid tail color behind the dots, or a glass type with a clearer fin and finer speckling. Match the photo to the fish in the tank.

In the wild

Grass came out of Japanese breeding, by hobby accounts in the late 1970s and early 1980s, as a variation on the mosaic strain. One account has Japanese breeders crossing glass guppies imported from Singapore into mosaic stock. Another has it appearing as a byproduct of a long inbreeding project on tuxedo mosaics, run over roughly 25 generations. Either way it is a domestic pattern with no wild equivalent.

Good to know

The grass factor works on the caudal and the dorsal together. A correct fish shows the same speckling in both fins rather than only in the tail. It descends from mosaic stock, and breeders cross grass onto other lines to give full metal blue grass or tiger grass. Dot size and spread drift between generations, so the pattern needs steady selection.

Did you know

Grass and glass are not separate lines. Hobby breeding notes report that a sibling cross inside a grass strain still throws both types, the solid-tailed grass and the clearer, finer-dotted glass. The two names describe fish that come out of the same spawn.

Weekly picks

Tank mates

Grass guppy is a peaceful, social species that keeps to the middle. These picks share a community profile with it, are safe together in both directions, and overlap on water type, temperature and pH.

Check the full mix in the stocking calculator

Common questions

Is a Grass guppy a different species from the Guppy?

No. A Grass guppy is a variety of the Guppy, Poecilia reticulata, and it wants the same tank, water and food as the species.

What size tank does a Grass guppy need?

A Grass guppy needs at least 13 gal (50 L). It spends most of its time in the middle.

How big does a Grass guppy get?

An adult Grass guppy reaches about 2.4 in (6 cm).

Related species