TankBud

Pygmy swordtail

Xiphophorus pygmaeus

FreshwaterFish

Pygmy swordtail (Xiphophorus pygmaeus)
Trondro tsara · CC BY-SA 4.0

Care at a glance

Temperature
75–82°F
24–28°C
pH
7.2–7.8
Adult size
1.6 in
4 cm
Minimum tank
11 gal
40 L
Temperament
Mostly peaceful
Social behavior
Social
Swim level
Middle
Difficulty
Medium
Breeding
Livebearer · Easy
Rarity
Common
Family
Poeciliidae
Origin
Pánuco River system (Rio Axtla), northeastern Mexico

Overview

The pygmy swordtail is a tiny, shy livebearer for the middle of a planted, hard-water tank. It suits a keeper with some experience.

Did you know

Male pygmy swordtails come in two forms that have nothing to do with age or health. Some mature small and start breeding early, while others grow larger and put on more color first. Both strategies persist in the same population, the small males by sneaking matings and the large ones by winning displays.

Caring for the pygmy swordtail

Keep pygmy swordtails in a group of at least six to eight, in a tank of 11 gal (40 L) or larger. Plant it densely, with driftwood, tall plants and some floating cover to hide in. Add a bit of current with the filter or a small powerhead to match their home streams. They are skilled jumpers, so a tight-fitting lid is a must.

Pygmy swordtails need hard, alkaline water and are not a soft-water or blackwater fish. Aim for 75 to 82°F (24 to 28°C), 8 to 20 dGH and a pH of 7.2 to 7.8, and keep the water well oxygenated. They are sensitive to ammonia and nitrite, so stay on top of water changes. Feed small flakes, micro pellets and frozen treats such as daphnia or baby brine shrimp.

Pygmy swordtails are mostly peaceful, but anything pushy will outcompete them. Keep them in a species tank, or only with small, gentle tank mates of similar size such as dwarf Corydoras. Aim for about one male to every three or four females, so courtship is spread out and no single female is pestered. Males set up a pecking order, but the squabbling stays at displays and almost never turns into real fighting.

Males reach about 3.5 cm, and females grow slightly larger. Females give birth to live young rather than laying eggs, and breeding pygmy swordtails is easy. A brood is small, usually only about 3 to 4 fry.

Never release unwanted fish or fry into local waterways. Livebearers can establish themselves where they do not belong, so check your local rules too.

Good to know

The pygmy swordtail, Xiphophorus pygmaeus, is a dwarf livebearer in the family Poeciliidae and one of the smallest swordtails. Unlike most of its relatives, the male lacks the long sword extension on the tail.

In the wild

Pygmy swordtails come from the Pánuco River system in northeastern Mexico, mainly the Rio Axtla. They live in flowing streams over hard, mineral-rich water.

Weekly picks

Tank mates

The pygmy swordtail is a mostly 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

What size tank does a pygmy swordtail need?

A pygmy swordtail needs at least 11 gal (40 L). It spends most of its time in the middle.

What temperature and pH does a pygmy swordtail need?

A pygmy swordtail is comfortable at 75–82°F (24–28°C) with a pH of 7.2–7.8.

What does a pygmy swordtail eat?

A pygmy swordtail eats small flakes and micro pellets. Give it frozen treats as well, such as daphnia or baby brine shrimp.

How big does a pygmy swordtail get?

An adult pygmy swordtail reaches about 1.6 in (4 cm).

How can you tell a male pygmy swordtail from a female?

Males stay a little smaller, at about 3.5 cm, while females grow slightly larger.

How does a pygmy swordtail breed?

A pygmy swordtail female gives birth to live young rather than laying eggs. Broods are small, usually only about 3 to 4 fry, and breeding them is easy.

Related species