Xiphophorus xiphidium (swordtail platyfish)

Xiphophorus xiphidium which is also known as swordtail platyfish belongs to the Poeciliidae family. Other common names are swordtail platy and spike-tail platy. Contrary to X.maculatus and X.variatus the species is rarely seen in the aquarium hobby. You should not confuse the species with Xiphophorus hellerii (swordtail) because of their similar common name.
The species is native to North America (Rio Soto La Marina system in Tamaulipas, Mexico). Because of the resilience of the species, they exist in a wide range of habitats, but in general, platies occur in lowland backwaters (lakes, swamps) and highland waters (lakes, rivers). The water in these habitats is somewhat hard and alkaline.
The wild form has mainly a grey colored body or yellow-ish body with sometimes black spots. The through selective breeding and hybridization, the species have more attractive spotting patterns. They have an average of 3 years lifespan, yet if cared properly can live up to 5 years.
The species have sexual dimorphism with the males being slightly smaller than females. Furthermore, male swordtail platies possess a shorter sword-like extension to the lower rays of the caudal fin from Xiphophorus hellerii (Swordtail). Swordtail platies have an average size of 2 inches (5cm). Male swordtail platies, like the rest of the Poeciliidae family, have their anal fins modified to the rod-shaped male’s reproductive organ, the gonopodium.
Like the rest of the poeciliid family, swordtail platies kept in groups, in a ratio of 1 male per 2 female, as they get stressed from the persistent chasing by male swordtail platies throughout reproduction. They are also suited for community tanks with peaceful species with a similar size and water chemistry. Some compatible species are other species of the Poeciliidae family like guppies and platies (If you don’t want hybridization, don’t put them together), peaceful small/medium size tetras, bottom dwellers like Ancistrus e.t.c.
Because of the natural habitat of Xiphophorus xiphidium, they should be kept in slightly hard alkaline water. Although swordtail platies can survive in a wide range of water parameters, a pH between 7.2-8.0, with a temperature between 20-25 Celsius, and hardness between 100-150 mg/l, suits the species.
Because most livebearers are active species and inhibit in highly oxygenated waters, consume more oxygen and produce more carbon dioxide, with the result that they need a reasonable space in the aquarium. An aquarium with pure 40 liters of water is suitable for a group of 4-5 swordtail platies. Plants are essential in the aquarium for livebearers as they provide shelter for stressed fish and their offspring.
Swordtail platies are omnivorous and can eat prepared food and small live-foods (brine shrimp, micro-worms, daphnia, white worms, tubifex). In nature, their diet consists of algae, insect’s larvae, and so on. Therefore, the nutrition of the species needs to include meat and plant source.
Swordtail platies are very easy to breed, you only need both genders. Like the rest of the poeciliid family, they give birth to live fry. The male chases the female, and when the female swordtail platy is ready, she stays immobile for a few seconds until the male fertilizes her. The action is repeated continuously by the male swordtail platy. It’s interesting that females can store sperm inside their body for months and get pregnant, without a male. The gestation period lasts 4-6 weeks and affected by environmental factors, diet, age and size of the female platy.
The female Xiphophorus xiphidium gives birth to 20-50 fry in one brood. The brood is affected by the age and size of the female swordtail platy. Keep in mind that Poeciliids are cannibals and eat their young. A planted tank may help the babies to survive. You can also place the offspring in breeding traps as well as in nursery tanks for their safety. The young swordtail platies reach their sexual maturity at the age of 4 months.


  1. Earl Schneider and Dr. Leon f. Whitney 1957, The Complete Guide
    to tropical fishes
  2. David Alderton 2005, 2008, Encyclopedia of aquarium and pond fish, Published in the United States by DK Publishing, ISBN 978-0-7566-3678-4
  3. Wilfred L. Whitern 1983, Livebearers, ISBN 0876665180
  4. Clarice Brough, Platies series: livebearers 3
  5. Xiphophorus xiphidium. Retrieved from https://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=165929#null

How useful was this post?

Click on a star to rate it!

Average rating / 5. Vote count:

Leave a Reply

Your email address will not be published. Required fields are marked *