TankBud

Variety of Guppy

Delta guppy

Poecilia reticulata

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

Also known as Green Delta Guppy, Blue Delta Guppy, Purple Delta Guppy

FreshwaterBrackishFish

Delta 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

Delta is a tail shape, not a color, so shops stack it with a color word: Blue Delta, Purple Delta, Green Delta. Males carry the finnage, which is why stores list Delta stock as males and sell females plain. Fin size varies between farms, and a large delta drags in strong flow, so aim the filter return along the glass.

In the wild

Delta is a show shape rather than a wild one, since wild male guppies carry a small rounded tail. Fancy breeders selected for tail spread over decades, and the International Fancy Guppy Association fixed the class in a standard. That standard defines the delta by the spread of the caudal at the peduncle rather than by fin size. No single breeder or country owns the shape, because farms everywhere work the same class.

Good to know

Tail spread is a selected, many-gene trait rather than a simple recessive. Fry from good parents show a range of spreads, and only the best hold the shape. The fin is enlarged by longer caudal rays with more membrane between them, and the body is unchanged. Females carry a much smaller caudal, and the IFGA runs them in their own female classes rather than against the males.

Did you know

The delta class is drawn by an angle. The IFGA puts deltas at 55 to 75 degrees off the caudal peduncle and veiltails at 40 to 50, so the two shapes are told apart by spread alone. A tail that opens past the top of the range sits outside the class rather than scoring above it.

Weekly picks

Tank mates

Delta 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 Delta guppy a different species from the Guppy?

No. A Delta 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 Delta guppy need?

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

How big does a Delta guppy get?

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

Related species