Swordtail Fish – Diet, Care and Breeding

Male and Female Orange Swordtails in Planted Aquarium


The swordtail is a very popular species of aquarium fish and it’s a great choice for the beginner aquarist. This is because it is tolerant to a range of conditions and has a very peaceful temperament. As the name suggests swordtails have a long, thin, elongated lower tail. Swordtails are livebearers, meaning they will give birth to live fry instead of eggs. Swordtails readily breed when kept in an aquarium of mixed sex, requiring little intervention. The young are very easy to rear and can be raised in the same aquarium as the adults.

Male Swordtail with lighter body coloration and orange with black tail.
Male Swordtail with lighter body coloration and orange with black tail.

There are several varieties of swordtail including Red Velvet Swordtail, Red Wag Swordtail, Neon swordtail, Pineapple Swordtail, Black Nubian Swordtail and Marigold Swordtails. The most popular is the solid orange variety and can usually be found in most fish stores. The cost of male swordtail is higher than that of the female due to the decorative nature of the fish.

Swordtail Requirements

Temperature – 64-82°F

pH – 7.0-8.3

Hardness – 12-30 KH

Max Size – 4”

Min tank size – 20 gallons

Diet – Omnivore

Care Level – Easy

Temperament – Peaceful

Cost – $4.49

Swordtails Notes & Facts

In the wild, swordtail are found in the warm waters of Mexico and span much of Central America. Swordtails thrive in flowing streams with dense vegetation. They are also found in small ponds and even in drainage pipes and vents.

Female Orange and Black Swordtail in a planted aquarium.
Female Orange and Black Swordtail in a planted aquarium.

They can easily adjust to different conditions when in captivity and for this reason Swordtails are a great beginner fish. The male swordtail can grow up to 6 inches while the female grows about 5 ½” however this is rare in captivity. Swordtails purchased in the store usually range from 1-2” in length. It’s important to have larger tank if you’re planning to keep swordtails due to the possibility of them growing to this size.

Swordtail Breeding & Fry

Swordtails are livebearers and will give birth to live young. Livebearers are an excellent fish to practice breeding because they will often breed with minimal intervention from the owners. Livebearer young are free swimming and fairly large when born, they have a much higher chance of growing to adulthood than fish raised from eggs.

NOTE: If you intend to breed swordtails, there should be more females in the tank than males. One male to three females is usually recommended for the highest chance of success.

During mating the males will continuously swim next to and nip the females. This can be stressful for the female and the continuing advances from the male can wear them out. It is important to house a larger number of females than males to reduce stress on individual females. Male Swordtails will also fight if kept in larger numbers in the breeding tank. It is important to have only a few males and lots of swimming space. Never overstock the breeding tank as this will only further increase stress in the fish.

The pregnant female shows a swollen belly and dark gravid spot when pregnant. It will become blatantly obvious the female is carrying young close to birth. The belly will be much larger than usual and the female Swordtail often struggles to move around the aquarium. On the days leading up to birth the Swordtail will become lethargic, may not eat, may hide toward the rear of the aquarium and very territorial. After birth it is important to remove the mother from the breeding tank to ensure the best chance of survival for the young fry.

Swordtail Feeding & Diet

In the wild Swordtails are omnivores. They will opportunistically feed on plants, insects and invertebrates. Aquarists should keep this diet in the aquarium by feeding a variety of processed and natural foods. A diversified diet should include frozen or live foods, blanched vegetables and flake or granular food. Vegetables such as cucumber medallions, zucchini medallions, broccoli and shelled peas can be lightly blanched in boiling water (to ensure they will sink in the aquarium) and fed to the Swordtails.

7 thoughts on “Swordtail Fish – Diet, Care and Breeding”

  1. Will the adult swordtails try to eat the newborn fish if you leave the adults in the tank? By Gregg L. Friedman MD

    1. I have had three generations of Swordtails and the adults seem to never bother the fry. The fry will seem to disappear sometimes because they will hide behind things like plants and rocks. Note: I have two pieces of shale in the back of the tank that hide the oxygen bubblers and they will go under the shales…..until they get to be about 1/2 inch…then they tend to be skittish in the bottom corner until they get to be 3/4 – 1 inch and seem to join the others with no notice from the males until they are old enough to bother….

  2. It’s been my experience that as long as they won’t fit in the mouths of the other tank mates and the match is right for housing together keep in mind the difference with the 2 tanks (nursery, community…) make sure the parameters are good and go for it I usually feed the home tank kids before I introduce any small fry so they don’t see it automatically as food as well as maybe even move a few decorations add a few hides and watch like any other time you’d add… Good luck sorry so late to answer! I hope it all worked out great!

  3. Excellent advise on breeding swordtails in a community fresh water tank. 5 Stars. By Gregg L. Friedman MD

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