Animal-World > Freshwater Fish > Livebearer Fish > Swordtail Fish

Swordtail Fish

Family: Poeciliidae

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Xiphophorous hellerii Photo © Animal-World: Courtesy Mathew O'Sullivan

   The most popular fish next to the Guppy is most certainly the Swordtail!

   The Swordtail is similar in shape to both the Platy and the Guppy though it has a bulkier body and a "sword" extending from the bottom of the male's tail fin. Today it is often thought to be named for this "sword" shaped extension of its tail fin, but the Swordtail was actually named for the sword like appearance of the male's anal fin!

   A beautiful male sporting a "sword" tail is one of the most striking physical characteristic possible by any aquarium fish. Even though there is no apparent purpose for this tail, it is 1/4 to 1/3 the total length of the fish. The wild species have an even more majestic tail, with swords up to 6 inches (15 cm). Though the "sword" tail is shorter in tank bred specimens it is complimented by the wonderful colors that are now available.

   Like the platys, they have been interbred to produce all kinds of interesting colors and different types of finnage. Some of the more common Swordtails are: Red, Red Wag, Red Tux, Painted, Neon Green, Marigold (and wag), Pineapple, Black, Red Twin bar, Sunset, and Gold Tuxedo swordtails.

   Extremely popular because they are one of the prettiest fish, the Swordtails are also easy to breed, fast growing and readily available.They are generally peaceful lively fish that swim in loosely grouped schools. Even though they are considered a good community fish, there are potentially many different behavior patterns and temperments. The individual fish vary from peaceful harmonious tankmates to bullies. Older males especially can tend to be aggressive toward each other and other species.

   Swordtails do best in a well planted tank with lots of room to swim around. Provide floating plants to protect the young as the parents often eat their fry. Like all livebearers, they do like a bit of salt though it is not necessary.

For more Information on keeping this fish see:
Guide to a Happy, Healthy Freshwater Aquarium

Dream Aquarium Build your own aquarium The Coolest and Funnest Screensaver in the World.

Distribution:
   The Swordtails are found in Central America from the Atlantic slopes of southern Mexico to Guadamala.
   There are several color varieties of the Swordtail Xiphophorous helleri as well as a variety of other Swordtails species. The Xiphophorous helleri is the most available and the other species, though similar, are not always as large and are often more delicate.
   The Spotted Swordtail Xiphophorous helleri was introduced as early as 1864, while the popular Green Swordtail Xiphophorous helleri was first introduced in 1909.

   Swordtails come in many colors and mixtures of colors, even in wild strains, that including red, green, black and albino though the most well known is red. There are now lyretail and high-fin varieties as males have been developed with exaggerated finnage and with two swords instead of one. Even some females also now have a sword. Most crosses are between the Platy or Moonfish Xiphophorous maculatus and the Swordtail Xiphophorous helleri.

Popular cross bred Swordtails:
   The Green Swordtail has a green body with red and yellow along the lateral line of the sides. The Green Wagtail Swordtail is this fish crossed with a Wagtail Platy and the Green Tuxedo Wagtail Swordtail is this fish crossed with a Tuxedo Wagtail Platy.
   The Red Swordtail is a Cross between the Green Swordtail and the Red Platy, sporting different shades of red and called the Brick-red Swordtail and the Velvet Red Swordtail. There is also the Red Wagtail Swordtail and the Red Tuxedo Wagtail Swordtail.
   A Variegated Swordtail is a mixture of colors with no set pattern.
   The Hybrid Swordtail, is the same fish as the Salt-and-Pepper Platy. No two fish are alike but contain bits of black, red, yellow, and green blotches. If they retain the "sword" then they are called a Hybrid Swordtail rather than Salt-and-Pepper Platy.

Pineapple Swordtail (female) Xiphophorous hellerii

Size - Weight:
The females get up to 4.5 inches (12 cm), males are somewhat smaller at 4.0 inches (10 cm).

Social Behaviors:
   They are generally considered a good community fish although they will sometimes eat their own (and other fishes) fry. Occasionally a Swordtail can become a bully, especially older males.

Sexual Differences:
Only the male has the "sword" extension on the bottom of the tail fin. The male is also slimmer and has a "sword" shaped anal fin called a gonopodium. The female has a fan shaped anal fin, is rounder of body, and will have a spawning patch at breeding time.

   There is an occasional tendency for a female Swordtail to change sex and develop a "sword" on her tail, especially when old or affected by parasites. She may even attempt courtship with another female, though the majority of the time they are infertile!

Water Region: Top, Middle, Bottom:
   These fish will swim in all areas of the aquarium.

Acceptable Water Conditions:
   Hardness: 12-30° dGH
   Ph: 7.0 to 8.3
   Temp: (64-82° F) 18-28° C

Breeding/Reproduction:
   The female Swordtail will generally have between 20 - 100 fry, usually up to 80. See the description of how to breed swordtails in Breeding Freshwater Fish - Livebearers.

Availability:
   The Swordtail is readily available.

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Latest Comments
My brother has just got 3 red sword tails. They are friendly with the other fish but do sometimes fin-nip the red dwarf gouramis. Kurt van Wyk 2008-08-15
Swordtails stay pregnant for 6 weeks. Did u know that there r blue swordtails now. Josh 2008-08-14
I have a one-year old female swordtail (without a male) and believe it or not she had young ones!! I am wondering how this can happen, or it swordtails breed with other different species of fish who would be the father. Laura Cachia 2008-07-24
I'm wondering how people tell if the swordtails are pregnant, since I have 2 males and 3 females. J 2008-07-22
I am wondering how long it takes for a pregnant swordtail fish to give birth. Oropeza 2008-07-17
Some of the coolest comments:
I think this is a very wonderful fish. They come in all different colors and will breed easily. But if you are like me and breed your fish these are a good fish to start on. The fry are kind of hard to take care of but if you know how to do it they will probably live. They are very easy to take care of and live a while. My oldest one is almost 7 months now in a heated aquarium around 75 F and fed twice a day. He lives with a mollie, african dwarf frog, female guppy, tiger barb, red platy and 5 jumbo neon tetras.(in a 10 gallon tank) Paige Felbaum 2004-04-06
Comments Dr Jungle REALLY Likes to Hear!
I like going to this site for answers to my livebearer questions.I own 4 swordtails,if you include the baby fry,1 large female guppie,and 30 of her fry.People say livebearers are only for beginners,but I like having fish that are easy to breed and tell apart.I could not imagine having a tank without atleast 2 livebearers.I would like to see more pictures or swordtail colors on this site.I enjoy seeing some of the vast color types!Thanks! Sarah . A . 2004-01-18

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Author: David Brough, CFS & Clarice Brough, CFS.

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