Swordtail Fact Sheet

The swordtail, a showy livebearer, is one of the most popular freshwater fish for beginners to the hobby. Over the course of ten years of fishkeeping, I have enjoyed keeping swordtails and their close relative, the platy. While they are extremely easy to care for, swordtail fish should not be overlooked by veteran fishkeepers-- they provide plenty of entertainment and beauty.

While swordtails are relatively easy to care for, they require good water conditions in order to truly thrive. If you keep your swordtail fish in good conditions, you'll be pleased by their active personalities and beautiful appearance.

Adult Size

Swordtails are one of the largest livebearing toothcarps. An adult can grow to five inches or more.

Tank Size

A trio of swordtails might be kept in a ten-gallon tank if the water is kept immaculately clean. Otherwise, twenty gallons is the bare-minimum for this active species.

Social Behavior

Swordtail fish do not school together, but they do require some degree of social interaction. Keep swordtails in groups of three or more. Alternatively, keep a single swordtail with two or more other livebearers, such as mollies or platy fish.

Tank Mates

Predatory fish seem to love the taste of swordtails. Avoid keeping them with large predators. Swordtails may bully petite livebearers like the guppy, and nippy fish like the rosy barb tend to bite the males' showy tails. Otherwise, swordtail fish can tolerate a wide range of tankmates.

Life Span

A well-kept sword tail can live to be up to five years old. Two to three years is more common in captivity.

Diet

Swordtails are omnivores, but their diet should include plenty of veggies. Flake, frozen and live food are all appropriate. Some stores offer livebearer flakes designed for these veggie-crazy fish.

Breeding

You will have no difficulty breeding swordtails; you're more likely to have trouble stopping them from breeding. Females will give birth to live young every four weeks. If the parents aren't removed from the tank, they will usually eat their young.

Water Parameters

Swordtails can live in a wide variety of water conditions, and they can endure unusually high levels of pollutants. Maintain a pH between 7-8. Swordtails can tolerate nitrate levels up to 30 ppm and ammonia levels up to 2 ppm.

Temperature

Swordtails can live without a heater if your home stays relatively warm. Keep the temperature between 70-82 degrees at all times.

Variations

Breeders have created dozens of unique varieties of swordtail fish, mostly by cross-breeding them selectively with related species. Pet stores may offer black, tuxedo, gold, neon, spotted, lyretail, albino, silver, red and blue swordtail varieties.