Swordtails, Freshwater fish, Information, Live-bearers and killifish

Swordtail: Complete Species Overview

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by Jason Matthews



If you are looking for freshwater fish species to add to your aquarium, you can’t go wrong with the Swordtail. These colorful and energetic fish varieties are an excellent addition to any community tank because they are peaceful. Additionally, they are ideal for beginners because they are very low maintenance.

So, how can you take care of the Swordtail? This article will examine in detail the physical features of this fish variety, temperament, tank requirements, tankmates, diet needs, and breeding requirements.


Scientific Name: Xiphophorus helleri

Common Names: Swordtail

Life Expectancy: 3 to 5 years

Adult Size: 3 to 5 inches


Beginner friendlyYes
Tank preferenceAll levels
Tank size20 gallons
Water temperature64 – 82 F
Water pHpH range 7.0-8.2
Water hardness12-30 dGH

Fun Fact

Swordtails have some specialty varieties that are not available anywhere else. These breeds are developed following several generations of inbreeding. Additionally, they are prone to immune issues, affecting their longevity.


This popular freshwater species is originally from Central and North America, specifically Mexico and Honduras. You can find them in different ecosystems with varying water depths, flows, and salinities. However, they are primarily found in areas with dense vegetation. Since they are from the Poeciliidae family, they are closely related to guppies and platys.

Swordtail fish have been carefully bred for their pattern and color combinations, which is why there are available in an array of choices.


swordtail in fish tank
Image credit: Darkocv, Depositphotos

Like their name, swordtail fish species are recognizable for their tail that resembles a sword. The male’s caudal fin has an elongated lower lobe, creating this sword-like protrusion.

Apart from this unique feature, swordtails have a strikingly similar body to the Southern platy. Males have a more colorful appearance than their female counterparts. Generally, they are bred in different color variations. The most common colors are vibrant yellow, red, orange, or black.

You could find these fish varieties in their natural green color or other variations, including neon, painted, pineapple, marigold wag, and red wag. Swordtails have upturned mouths and pointy snouts. They are the widest where the pelvic and dorsal fins appear at the midsection area.

Average Size

Swordtail fish are medium-sized species. As adults, they grow to about 3 to 5 inches, while some may grow to 5.5 inches in length.

Gender differences

You can easily differentiate between the male and female swordtail. Males have the unique sword feature on the caudal fin, while females have a rounded tail edge. Because of this, females tend to have thicker bodies than males. In addition, females have a fan-shaped anal fin, while in males, it’s pointed.


Swordtail fish are generally peaceful, making them a great addition to your community tank. However, they are also flashy and active; therefore, they’ll take up a lot of the space in the top and middle levels of the tank. Although they are not a shoaling species, they prefer to be kept with other fish varieties.

Although they are naturally peaceful, they have the potential to be aggressive. They exhibit these characteristics, especially when there are multiple males in the same tank. Male swordtail species can be territorial; therefore, you should add a higher ratio of females to maintain peace.


If you plan to keep swordtail, they get along with like-minded species. They should not be kept alone; you should add them in groups of 4 to 5. As mentioned, having more females is advisable; therefore, you can keep four females and one male.

Furthermore, you should keep swordtail fish with species of the same size and temperament. Avoid aggressive species because they can’t defend themselves; they tend to become shy.

The ideal tankmates include mollies, platys, neon tetras, rosy barbs, celestial pearl danios, dwarf gouramis, and angelfish.

Tank Size and Conditions

Since they are medium-sized fish species, they need a bigger tank than 10 gallons. You can start with a 15-gallon tank; however, since this species is active, they might need extra space, about 20 gallon – 30 gallons. Therefore, if you are planning to keep them in groups in a community tank, you should go for the bigger tank.

In the wild, swordtail fish live in warm rivers and streams with tons of vegetation. However, they can easily adapt to any environment with fresh water.  This is why they are such a simple species to take care of.

As you stock them in a tank, ensure that the water conditions are ideal. Keep the temperatures between 64-82F, pH levels between 7.0 – 8.4, and water hardness between 12-30 dGH. Additionally, ensure that the tank has enough space and plants for hiding.


As natural omnivores, swordtail fish will eat almost anything in the wild, from larvae to tiny microorganisms and plants. In captivity, you should feed them a varied diet containing commercial food and high-protein snacks. Ensure that they eat nutrient-rich pellets or flakes.

To balance the diet, you can also add algae flakes. They also enjoy feeding on frozen, live, and freeze-dried foods. Include some bloodworms and brine shrimp. 

Whether you have adults or juveniles, you should feed them two small meals every day. After two minutes, you can remove all the leftovers to prevent water contamination.


Swordtail species are livebearers, which means they are quick to spawn. With the right conditions, females can give birth once every 28 days. 

It would be best if you had a separate breeding tank to increase the chances of the fry surviving. In the breeding tank, add some plants and raise the water temperatures slightly for the fry to survive.

Generally, swordtails mature in three months and can birth up to 50 fry per spawning. Therefore, if you don’t want more fry, you should separate males from females before they reach reproductive maturity.


If you are starting out as an aquarist, you can’t go wrong with the swordtail. This freshwater species is easy to take care of as long as you take care of it properly. Thanks to their colorful appearance and active lifestyle, they are a fun addition to your aquarium.


Jason Matthews

My name is Jason Matthews, and welcome to my website. When other kids were bragging about how their dog could sit and roll over, I was bragging about my latest Betta Fish and the cool sea castle I just added to his aquarium. 

Jason aquariume

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