Koi Kohaku Swordtail (Xiphophorus hellerii)

The Koi Kohaku Swordtail, Xiphophorus hellerii, is a bright domestic swordtail strain with a red-orange and white pattern inspired by koi colouration. It is a lively, confident livebearer for aquarists who want colour, movement and a fish that is usually straightforward to keep when the aquarium is planned properly. Compared with smaller platies, swordtails are more streamlined, stronger swimmers and more likely to use the full length of the tank, so this listing has been expanded with practical care notes rather than a short product blurb.

This variety suits a mature hard-water community aquarium with open swimming room, planted edges and calm but active tank mates. Males develop the classic sword extension on the lower tail, while females are usually larger and deeper-bodied. The current listing keeps the approved product image, preserves the existing size options and adds clearer guidance on water, feeding, group balance and delivery so the page is useful for shoppers and search engines without forcing keywords into unnatural sentences.

Koi Kohaku Swordtail Quick Care

Natural Background and Aquarium Behaviour

Xiphophorus hellerii is a Central American livebearer associated with vegetated streams, rivers, springs, canals and ponds. Wild swordtails are adapted to active swimming, mixed plant and open-water cover, and a diet that includes small invertebrates as well as plant material. The Koi Kohaku form is a domestic colour strain, so the exact red-white pattern is bred for the aquarium trade, but the underlying body shape and behaviour still follow the swordtail pattern.

In the aquarium, expect constant movement through the middle and upper water. They are not shy fish once settled, and they often become one of the most visible species in a community display. Males may display to each other and chase females, so group balance matters. A single male with several females is usually calmer than multiple males in a short tank. If you keep more than one male, use extra length, plants and visual breaks so weaker fish can move away.

Tank Setup for Koi Kohaku Swordtails

Start with a secure lid because swordtails are athletic jumpers. Use planted sides and background cover, but leave the central swimming lane open. Hardy plants such as Vallisneria, Java fern, Anubias, Hygrophila and floating cover all work well. The goal is not a dense jungle from front to back; it is a balanced layout with refuge for females and open water for display.

Water Quality and Maintenance

Koi Kohaku Swordtails are hardy, but they do not do their best in neglected water. Keep ammonia and nitrite at zero, nitrate controlled by water changes and plants, and minerals stable. In most hard-water UK tap-water areas, they are easier to keep than soft-water species because you normally do not need to chase very low pH or remove hardness.

A weekly partial water change is a sensible baseline, especially if the group is breeding or sharing the tank with other active livebearers. Use dechlorinator for new water, match temperature sensibly, and avoid sudden swings. If females are producing fry, keep maintenance gentle but consistent; crowded fry and adults can quickly increase bioload.

Feeding Koi Kohaku Swordtails

Feed a varied omnivorous diet. A quality flake or small livebearer pellet can be the staple, with vegetable-rich foods, spirulina, fine frozen foods and occasional live foods used for variety. They browse, pick and compete actively, so small regular meals are better than one heavy feed.

Tank Mates and Group Planning

Good companions include other peaceful hard-water community fish that enjoy similar conditions. Platies, mollies, many rainbowfish, peaceful barbs and suitable bottom dwellers can work if the aquarium is large enough. Avoid slow long-finned fish, persistent fin nippers, very tiny tank mates and soft-water species that need different chemistry.

For related livebearer options, compare this fish with Swordtail Wagtail Lyra, Albino Koi Swordtail, Assorted Swordtail and Koi Tricolour Swordtail. These internal links help shoppers choose by colour, size and availability without repeating the same sales phrase.

Breeding and Fry Notes

Swordtails are livebearers, which means females give birth to free-swimming young rather than laying eggs. In a mixed group, fry may appear without special effort. Dense plants, floating cover and fine-leaved growth give young fish somewhere to hide. Adult fish may eat fry, so use a separate grow-out tank if you want to raise larger numbers.

Do not overstock because successful livebearers can multiply quickly. A balanced adult group, regular water changes and sensible feeding are better than letting a small aquarium fill with mixed-age juveniles. If you want a display tank rather than a breeding project, keep group size modest and plan rehoming before fry appear.

Ordering, Size Options and Delivery

Order when your aquarium is cycled, stable and ready for active livebearers. Tropical Fish Co ships livestock by licensed live-animal courier, with live-arrival cover on eligible orders. First-time customers can use WELCOME10 for 10% off where the code is active. The best result comes from matching the fish to the right water and tank size before checkout, not from squeezing them into a small temporary setup.

Koi Kohaku Swordtail FAQs

Are Koi Kohaku Swordtails beginner friendly?

Yes, they can suit beginners with hard tap water, a cycled aquarium and enough swimming room. They are less suitable for tiny tanks.

Do swordtails need to be kept in groups?

They are social livebearers. A small group is best, with more females than males if sexes are mixed.

Will they eat their own fry?

Adults may eat fry. Add dense plants or use a separate grow-out tank if you want to raise young fish reliably.