Product Details

Kohaku Swordtail – Xiphophorus hellerii

The Kohaku Swordtail is a striking captive-bred livebearer selected for clean red-and-white koi-style colouration. As an ornamental strain of Xiphophorus hellerii, it is active, hardy and well suited to spacious community aquariums with stable, mineral-rich water. Swordtails are larger and more energetic than platies or guppies, so this variety should be given plenty of swimming room, plant cover and carefully chosen peaceful tank mates.

Key Identification:

Common Name: Kohaku Swordtail
Other Names: Kohaku Sword, Red and White Swordtail, Koi Swordtail, Fancy Swordtail, Green Swordtail
Scientific Name: Xiphophorus hellerii
Corrected Spelling: Xiphophorus hellerii
Fish Type: Livebearer / Swordtail
Water Type: Freshwater, with tolerance of slightly brackish conditions

Natural Range & Habitat:

Wild Xiphophorus hellerii is native to North and Central America, from Mexico through to parts of Central America. It is found mainly in streams and rivers, but also occurs in warm springs, weedy canals and ponds. Natural habitats are often vegetated and provide a mix of open swimming areas, plant cover and flowing or well-oxygenated water.

The Kohaku Swordtail is a captive-bred aquarium strain, so its red-and-white colour pattern is a selectively bred trait rather than a wild-type feature. Aquarium care should still reflect the species’ need for space, stable hard water and clean, well-maintained conditions.

Appearance & Adult Size:

Kohaku Swordtails usually show a white, cream or pale body with red, orange-red or coral patches. The colour pattern can vary between individuals, with some fish showing red over the head and back, others showing larger body patches or a more broken koi-style pattern. Males develop the classic swordtail extension on the lower part of the tail and a gonopodium, while females are larger, deeper-bodied and do not develop the same sword.

Adults commonly reach around 10–12 cm in aquariums, with large females capable of growing bigger. Because swordtails are active, long-bodied livebearers, they need more aquarium space than smaller livebearers of similar temperament.

Aquarium Suitability:

Kohaku Swordtails are well suited to larger peaceful community aquariums, planted livebearer displays and active tropical setups. They do best in mature aquariums with stable water quality, gentle to moderate flow, plant cover and plenty of open swimming space.

They are not suitable for soft acidic blackwater aquariums, tiny tanks, aggressive cichlid setups, predator communities or unheated aquariums that drop too cold. Although hardy, swordtails should not be used to cycle new aquariums.

Recommended Aquarium Size:

A practical minimum is 100–120 litres for a small group, with a tank length of at least 80–100 cm recommended. Larger aquariums are better for mixed communities, adult females and groups containing more than one male.

Swordtails are social livebearers and are best kept in groups. If keeping males and females together, keep more females than males to reduce persistent male attention, ideally around two or more females per male. Multiple males need extra space and visual barriers, as males may chase and compete.

Water Conditions:

Temperature: 22–28°C
pH: 7.0–8.0
Hardness: Moderately hard to hard
Additional Notes: Swordtails need mineral-rich, stable water and should not be kept long term in very soft, acidic conditions. Keep ammonia and nitrite at zero and maintain low nitrate with regular water changes. They appreciate clean, fresh water and can struggle in neglected aquariums, so consistent maintenance is important.

Temperament & Tank Mates:

Aquarium Category: Community Fish

Kohaku Swordtails are peaceful community fish, but they are active and males can be persistent. Suitable tank mates include platies, mollies in compatible water, guppies, Endler’s livebearers, peaceful tetras that tolerate harder water, rainbowfish, danios, Cory-type catfish in compatible conditions, bristlenose plecs and other robust peaceful community species.

Avoid large predators, aggressive cichlids, very soft-water specialists, severe fin-nippers and very shy slow feeders that may be intimidated by active livebearers. Do not keep males in cramped conditions where chasing cannot be spread out.

Feeding:

Kohaku Swordtails are easy-feeding omnivores. Offer quality flakes, small pellets or granules as the staple diet. Supplement with frozen or live foods such as daphnia, brineshrimp, cyclops, mosquito larvae and bloodworm. Include vegetable matter such as spirulina flakes, algae-based foods or blanched greens to support digestion and colour.

Feed measured portions that are eaten quickly. Swordtails are active feeders and can become overweight if overfed.

Behaviour in the Aquarium:

This is an active, visible livebearer that usually swims through the middle and upper areas of the aquarium. Males display with their swordtail extension and may chase females or rival males. Plant cover, open swimming room and sensible sex ratios help keep behaviour manageable.

Like other livebearers, females give birth to free-swimming fry rather than laying eggs. In a planted aquarium, some fry may survive among moss, floating plants and dense cover. Females can also store sperm, so fry may appear even if males are removed.

Care Notes:

Add Kohaku Swordtails only to a mature, fully cycled aquarium. Maintain hard, alkaline water, stable temperature and regular partial water changes. Provide plants and cover, but leave open swimming space. Use a secure lid, as swordtails are active and may jump if startled.

Because this is a captive-bred colour strain, red coverage, white base colour, body pattern and sword length can vary naturally between individual fish. The best colour is usually seen in settled fish with good diet and stable water.

Recommended For:

Beginner to intermediate

Availability:

Common to occasional / Captive-bred ornamental strain

Image Disclaimer:

All images are a visual representation of the fish you will receive, made to be as accurate as possible. Natural variation in size, red coverage, white colour, body pattern, sword length and markings can occur between individual fish.