Swordtail Fish: Beauty of the Male’s Sword

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I have always been fascinated by the colorful and lively nature of Swordtail fish.

These freshwater fish are a popular choice for aquarium enthusiasts due to their vibrant colors, easy maintenance, and peaceful nature.

Swordtails are part of the Poeciliidae family, which includes other popular fish like Guppies and Mollies.

Swordtails are known for their unique sword-like tail that distinguishes them from other fish.

They come in a variety of colors, including red, orange, black, and green.

These fish are also known for their active behavior, making them a fun addition to any aquarium.

Swordtail fish are relatively easy to care for and can adapt to a wide range of water conditions, making them a great choice for beginner fish keepers.

Join us as we uncover the secrets of the Swordtails, and learn how you can create a thriving and harmonious environment for these vibrant and hardy swimmers in your home aquarium.

Quick Facts

CategorySwordtail Fish
North and Central America (Mexico and Honduras)
SizeUp to 6 inches (15 cm) in length
Unique FeatureSword-like tail fin (only in males)
Tank SizeMinimum 20 gallons (40-gallon for a group)
Water Temperature72-79°F (22-26°C)
pH Level7-8.2
CompatibilityPeaceful community fish
Ideal Tank MatesGuppies, Mollies, Tetras, Corydoras, Cherry Barbs
Green Swordtail fish

Swordtail Fish Overview

The enchanting Swordtail fish (Xiphophorus helleri) boasts a rich history and diverse origin that spans across North and Central America.

These fascinating fish primarily inhabit the freshwater rivers and streams of Mexico and Honduras, where they swim among dense vegetation and thrive in fast-flowing waters.

Over time, their vibrant colors and unique appearance caught the attention of aquarists worldwide, making them a popular choice for home aquariums.

Swordtail fish belong to the family Poeciliidae, which includes other well-known species such as Guppies, Mollies, and Platies.

This family is renowned for its livebearing nature, meaning that Swordtails give birth to live, free-swimming fry rather than laying eggs.

This fascinating trait, combined with their hardy constitution and ease of care, makes Swordtails a particularly attractive option for beginner fish keepers.

These captivating fish have been bred for generations, resulting in numerous varieties that exhibit a wide range of colors, patterns, and fin shapes.

Swordtails can grow up to 6 inches (15 cm) in length, with males generally being more slender and featuring the signature sword-like extension on their tail fin.

Females, on the other hand, have a more rounded tail fin and are typically larger and more robust.

Swordtails are known for their adaptability, which allows them to acclimate well to various water conditions.

This makes them an excellent candidate for a community tank, where they can thrive alongside a diverse array of compatible species.

With a life expectancy of 3-5 years when cared for properly, Swordtail fish offer years of enjoyment and stunning visual appeal for aquarists of all experience levels.

Swordtail Neon


The Swordtail Fish has a distinctive body shape.

They are streamlined and have a wide tailfin, pointy snout, and upturned mouth.

The fish are widest where the dorsal and pelvic fins appear at the midsection.

The male Swordtail Fish has a long and pointed tail, which is where they get their name from.

The female Swordtail Fish has a more rounded and fan-shaped tail.

The Swordtail Fish can grow up to 6 inches in length, with the females being larger than the males.

In addition to their body shape, Swordtail Fish also have a few other physical features that are worth noting.

They have a small dorsal fin on their back, as well as an anal fin on their underside.

These fins help the Swordtail Fish to swim and maneuver through the water.

They also have a pair of pectoral fins on their sides, which they use to maintain balance and stability.

Overall, the Swordtail Fish is a beautiful and unique fish that is sure to catch your eye.

Whether you are a seasoned fish keeper or a beginner, the Swordtail Fish is a great addition to any aquarium.

Black Swordtail Fish

Types of Swordtail Fish

If you’re interested in adding swordtail fish to your aquarium, there are several types of swordtail fish to choose from.

Here are some of the most popular swordtail fish varieties that you may come across:

Swordtail Varieties

Green Swordtail: This is the most common variety of swordtail fish. The green swordtail has a greenish-yellow body with a black stripe running horizontally along its side.

Neon Swordtail: This variety has a bright orange body with a neon blue stripe running horizontally along its side.

Pineapple Swordtail: The pineapple swordtail has a yellowish-orange body with black spots scattered all over it.

Painted Swordtail: The painted swordtail has a white body with black spots and a red tail.

Marigold Wag Swordtail: This variety has a yellowish-orange body with a red tail and black spots.

Hi Fin Lyretail Swordtail: This variety has a long, flowing tail that resembles a lyre. It comes in various colors, including red, orange, and yellow.

Albino Swordtail: The albino swordtail has a white body with pink eyes.

Black Swordtail: This variety has a black body and a red tail.

Wild Swordtail: This variety has a grayish-green body with a black stripe running horizontally along its side.

Xiphophorus Hellerii: This is the scientific name for the common swordtail fish. It has a greenish-yellow body with a black stripe running horizontally along its side.

As you can see, there are many different types of swordtail fish to choose from.

Each variety has its own unique characteristics and colors, so take some time to research and choose the variety that best fits your aquarium and personal preferences.

Swordtail Fish Colors

If you’re interested in keeping swordtail fish, one of the most exciting things about them is the variety of colors they come in.

Here are some of the most common colors you’ll find in swordtail fish:

  • Red: One of the most popular colors for swordtails, red is a bright and eye-catching hue that adds a pop of color to any aquarium.
  • Yellow: Yellow swordtails are another popular choice, and they come in a range of shades from pale lemon to deep gold.
  • Black: Black swordtails are a dramatic and striking addition to any tank. They often have iridescent blue or green hues that shimmer in the light.
  • Green: Green swordtails have an olive-green base color with a brown lateral stripe that runs through the sword. They’re a popular choice for those who want a more natural-looking fish.
  • Marbled: Marbled swordtails have a mix of colors and patterns, including black or blue marbling. They’re a unique and eye-catching addition to any aquarium.

It’s worth noting that swordtails can also come in a variety of other colors, including orange, blue, and white.

Some breeders have even developed new colors and patterns through selective breeding, so you may come across swordtails in shades you’ve never seen before.

Size & Lifespan

Swordtail fish are admired not only for their vibrant colors and captivating appearance but also for their moderate size and relatively long lifespan.

Swordtails exhibit sexual dimorphism, meaning males and females differ in size and appearance.

Males are generally more slender and can grow up to 5.5 inches (14 cm) in length, including their signature sword-like tail extension.

Females, on the other hand, tend to be larger and more robust, growing up to 6 inches (15 cm) in length with a rounded, fan-shaped tail fin.

Their moderate size makes Swordtails suitable for a variety of tank setups, as long as they have adequate swimming space and compatible tank mates.

When properly cared for, Swordtail fish have a life expectancy of 3-5 years.

Their longevity is influenced by factors such as water quality, diet, tank conditions, and overall health.

Behavior & Temperament

Swordtail fish are known for their social and peaceful nature, making them an ideal choice for community aquariums.

They thrive in groups and enjoy the company of other Swordtails or compatible species.

To ensure a harmonious environment, it’s recommended to maintain a group of at least five Swordtails with a mix of males and females.

Maintaining a ratio of one male to at least two or three females can help minimize any aggressive behavior or persistent chasing during mating.

These vibrant fish are active swimmers, exploring all levels of the aquarium with a preference for the mid and upper regions.

Providing sufficient swimming space and hiding spots will help with their well-being, as it allows them to exhibit natural behaviors and reduces stress.

Swordtails are known for their curiosity, often investigating new additions to the tank or interacting with their human caregivers.

One notable aspect of Swordtail behavior is their ability to jump.

This skill is a natural response to perceived threats or escaping predators in the wild.

Because of this, it is advisable to always have a secure lid on the tank.

Breeding behavior in Swordtails can lead to some aggression or territorial tendencies, especially among males.

By maintaining the recommended male-to-female ratio, you can mitigate these issues and ensure a harmonious tank environment.

Swordtail fish are generally more active during the day but may exhibit some nocturnal behaviors.

A consistent day-night light cycle will help regulate their biological clock and create a stress-free environment.

Tank Requirements

Swordtail fish are hardy and adaptable, making them perfect for beginners.

They thrive in water temperatures between 72-79°F (22-26°C) and a pH range of 7-8.2.

I recommend a minimum tank size of 20 gallons for Swordtail fish.

These fish are active swimmers and need plenty of space to move around.

If you want to keep a group of Swordtails, you will need a larger tank.

A 40-gallon tank is a good size for a small group of Swordtails.

Swordtails can jump, so ensure your aquarium has a secure lid to prevent any escape attempts.

As they originate from rivers and streams, Swordtail fish appreciate a moderate water flow in their tank.

Adding live plants, rocks, and driftwood can provide hiding spaces and help replicate their natural habitat.

Tank Mates

Swordtail fish are peaceful community fish that can coexist peacefully with various other species.

Choosing the right tank mates will ensure a stress-free environment and prevent conflicts or injuries.

Ideal tank mates for Swordtail fish include:

  • Other livebearers: Guppies and Mollies are excellent choices, as they share similar water requirements and have compatible temperaments. Be weary of adding Platy fish as they can interbreed.
  • Tetras: Peaceful species of Tetras, such as Neon Tetras, Lemon Tetras, Cardinal Tetras, or Rummy Nose Tetras, can coexist well with Swordtails.
  • Corydoras: These gentle, bottom-dwelling catfish are ideal companions, as they help maintain the tank’s cleanliness and do not compete for the same swimming space.
  • Small Barbs: Cherry Barbs or Gold Barbs can make suitable tank mates, provided they are housed in a group to minimize any potential fin-nipping behavior.
  • Dwarf Gouramis: These peaceful, slow-moving fish can be a colorful and compatible addition to a Swordtail tank.
  • Rasboras: Harlequin Rasboras and other peaceful Rasbora species can also make great tank mates.
  • Snails and Shrimp: Invertebrates like Nerite Snails, Amano Shrimp, or Cherry Shrimp can coexist peacefully with Swordtails and contribute to maintaining a clean tank.

Closely monitor your aquarium, especially when introducing new tank mates, to ensure compatibility and address any signs of aggression or stress promptly.

By carefully selecting the right tank mates for your Swordtail fish, you can create a diverse, thriving, and harmonious aquatic community.

Female Swordtail Fish
Female Swordtail Fish


Swordtail fish are omnivores, which means they consume both plant and animal matter.

Offer them a high-quality flake or pellet food as a staple diet.

Supplement their diet with live or frozen foods such as brine shrimp, daphnia, and bloodworms, along with blanched vegetables like spinach and peas.

Feed them once or twice a day, providing only as much food as they can consume within 2-3 minutes.

Common Health Issues

As with any living creature, Swordtail fish are susceptible to various health issues.

In this section, we will go over some of the most common health issues that these fish face, and how to address them.

Diseases and Treatments

Swordtail fish can suffer from all the common ailments, including ich, fin rot, and swim bladder disease.

Ich is one of the most widespread health issues in the fish-keeping world.

It’s an ectoparasite that ravages a fish’s immune system.

Typically manifesting itself as white dots all over the body, it’s important to address it as soon as possible.

Fin rot is another common issue that can be caused by poor water quality or injuries.

Swim bladder disease can also occur, causing the fish to have difficulty swimming or even causing them to swim upside down.

Treatments for these ailments include medication, water changes, and improving water quality.

Red Wagtail Swordtail Fish


Swordtails are livebearers, meaning they give birth to live, free-swimming fry instead of laying eggs.

Breeding Swordtail fish is relatively easy, making it an enjoyable experience for beginners.

To encourage breeding, maintain a ratio of one male to at least two or three females, as males can become aggressive during mating.

Once the female is pregnant, you can expect the birth of 20-100 fry in approximately 28 days.

To increase fry survival rates, use a breeding box or separate tank with hiding spaces, as adult fish may eat the fry.

Are Swordtail Fish Right For You?

Deciding whether Swordtail fish are the right choice for your aquarium involves considering their care requirements, compatibility, and your experience level.

These beginner-friendly fish are hardy and adaptable, making them suitable for those new to fishkeeping.

However, they require a spacious tank, stable water parameters, and compatible tank mates to thrive.

If you’re willing to invest time and effort in their ongoing care and maintenance, Swordtails can be a rewarding and visually captivating addition to your aquatic community.


How many swordtails should be kept together?

These fish prefer to be in groups of between 4 to 6 individuals. You will need to keep to the ratio of two to three females for every male.

Do swordtails get along with other fish?

Swordtails are peaceful community fish so they do get along with other fish. They need tank mates that are just as peaceful as them and also prefer fish of the same size or smaller.

What fish can breed with swordtails?

Platy fish can breed with Swordtails so it is advisable not to mix these two species unless you intentionally want them to interbreed.

Can you keep swordtails with guppies?

Yes, they make excellent tank mates as they share the same water parameters and have similar temperaments.

Can Molly mate with swordtail?

No, they cannot as Mollies belong to a different genus.

Can female swordtails turn into males?

There has been some reported cases of this happening but it is very rare.

Do swordtails eat small fish?

They will eat very small fish. That is why any fry that they have are at risk of being eaten.

Photo of author


Irma Bense is the founder of BetterFishkeeping.com. She has over 42 years of experience in keeping fish.She has kept both freshwater and saltwater fish through the years.She has extensive knowledge in breeding numerous species of fish from Show Guppies, Cory Catfish, German Blue Rams to Apistogrammas.You can learn more about Irma on the 'About' page.

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