Koi Swordtail

 Quick Care Facts

• Care Level: Easy   • Temperament: Peaceful   • Maximum Size: 4"
• Minimum Tank Size: 20 gallons   • Water Conditions: 64-82° F, KH 12-30, pH 7.0-8.3
• Diet: Omnivore   • Origin: Central America   • Family: Poeciliidae
• Species: Swordtails   • Aquarium Type: Community

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The Koi Swordtail (Xiphophorus helleri) is a color morph originating from the popular group of fish collectively known as Swordtails. Koi Swordtails receive their common name from their similarity to the popular selectively bred carp call Koi (Nishikigoi), more specifically the Kohaku, Sanke and Show Koi varieties with exhibit the popular orange, red & black colored areas over a milky white body.

As with their Koi namesake, the deep contrasting reddish orange and black marks wrap around a milky white, semi-transparent body which creates a truly beautiful fish. The male Koi Swordtail has flowing, feathered fins with a distinct extension on the lower part of the tail, resembling a sword. While the female does not have the distinguishing, sword-like tail, her Koi coloration still makes her a stunning specimen to behold.

The Koi Swordtail is a member of the group of fish commonly known as Swordtails, which are some of the most widely kept and popular of the tropical community fish species available within the hobby. Swordtails are a species of live-bearing fish that flourish in the rivers and streams of Central America. Known for their prolific breeding ability, Swordtails have been captivity bred at tropical fish farms for many years.

Their popularity with aquarium hobbyists stems from their ease of care, bright coloration (orange, red, yellow), relative abundance and low cost. Swordtails do tend to have shorter life spans than other tropical community fish, with the average life span of 2 to 4 years. Koi Swordtails, like other Swordtails, are known to be jumpers so it is important to provide an adequate cover over the aquarium.

They have a penchant for taking flight, which is taken from their natural habitat, where while swimming at the waters surface in search of food they would use their ability to jump from the water to avoid ambush predators who typically strike from below.

Koi Swordtails are an easy species to keep within the home aquarium environment, as they can tolerate a wide range of water conditions. Koi Swordtails will also co-exist peacefully with most species of tropical freshwater fish available within the hobby, and will also do fine in pairs or groups. They typically swim near the water surface or mid-water, and prefer that the aquarium be decorated with some plants, driftwood, root and rocks to provide them cover when they feel threatened.

Since they originate from rivers and streams in the wild, Koi Swordtails prefer to have some water current within the aquarium to better simulate their natural surroundings. Koi Swordtails do not have specific filtration or lighting requirements and can easily be maintained with most any Power Filter or Canister Filters available within the hobby.

The Koi Swordtail (Xiphophorus helleri) will eagerly consume a wide variety of foods ranging from plant matter and algae to meaty foods and small insects. In nature they prey on small crustaceans, insects, larvae and small worms that they find living in and near the river bank vegetation. Koi Swordtails also consume a good amount of plant matter and algae within their natural diet, thus is recommended that they be fed both meaty and vegetable based foods in order to support a healthy immune system and slime coat.

Feed this species 2 to 3 times per day the amount of food that they will consume within 3 to 5 minutes. Recommended commercial foods include: quality flake, small pellets, crisps, frozen foods, tubifex worms, blood worms, cyclop-eeze, dried algae flakes or wafers and brine shrimp.

As with most live-bearers, the Koi Swordtail is a prolific breeders that is easy to breed within the aquarium environment. Swordtails can give birth to as many as 100 fry during a single spawn and will spawn roughly every 30 to 40 days. Essentially any aquarium containing at least a male and female Swordtail will eventually have a pregnant female. It is easy to tell if the female is pregnant as she will develop a dark triangular shaped gravid spot near her anal vent, which will get larger and darker as the pregnancy progresses.

In order to protect the fry, a spawning box or dense floating vegetation should be provided as cover to protect the fry from the adults as they will typically eat the fry. Once the sex of the fry is determined, the males should be separated because the Koi Swordtail can begin breeding as young as three months of age.