Black Swordtail

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Xiphophorus helleri - Heckel, 1848
Black Swordtail

Color variant of the Green Swordtail. Aaron Norman


A classic livebearer and great beginner's fish, colorful and easy to keep.

The Swordtail takes its name from the long, saberlike extension of the male’s tail fin, which is rounded in females. The original wild form is an olive-green color. The sword itself comes in a variety of hues, from greens to yellows to oranges and reds, and many combinations thereof. They have been selectively bred to produce a large array of colors and finnages.

Family: Poeciliidae

Other common name(s):

Native range:

Habitat: Needs a long, rather than tall, aquarium, with plants restricted to the sides and back, and plenty of room to swim in the center. Good jumpers, so a tight-fitting cover is a must.

Maximum length: 11.5 cm (5 in)

Minimum aquarium size: 76 L (20 gal)

Water: Freshwater 22 °C (72 °F) - 26 °C (79 °F)

General swimming level: Midwater to top


Omnivore. In the wild, plant material and insects form the major portions of their diets. In the aquarium, they will consume a wide variety of foods, such as good-quality flakes, freeze-dried , frozen or live foods like brine shrimp and mysid shrimp. To round out their diets, also offer algae-based foods, such a Spirulina flakes.

Aquarium Compatibility

Males are apt to bully one another, so keep only one male to several females. Sometimes they may even be a little aggressive toward other species, although they can be housed with a variety of generally peaceful, community tank fishes.

Special Care

Good jumpers; a tight-fitting cover is a must.


Bears live young that emerge free-swimming and ready to start feeding. Will crossbreed with the closely related Platy, so it is best not to keep them in the same aquarium if you desire pure offspring.


Swordtails have reportedly been released into waters in Africa, perhaps for mosquito control, and have established themselves at least in Namibia.

Reference: 101 Best Tropical Fishes
Image credit: AN
Text credit: KW