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.
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.
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.