Product Details

Kohaku Swordtail – Xiphophorus hellerii

Overview:

The Kohaku Swordtail is a striking red-and-white colour strain of the classic Swordtail livebearer. Inspired by the “Kohaku” red-and-white patterning familiar from koi varieties, this aquarium-bred form of Xiphophorus hellerii brings bright colour, constant movement and hardy livebearer behaviour to a peaceful community aquarium. Swordtails are larger, faster and more energetic than platies, so they need a longer tank, clean well-oxygenated water and sensible group ratios.

Key Identification:

Common Name: Kohaku Swordtail
Other Names: Red White Swordtail, Kohaku Helleri, Kohaku Sword, Red and White Swordtail, Green Swordtail
Scientific Name: Xiphophorus hellerii
Older / Misspelt Trade Form: Xiphophorus helleri
Fish Type: Livebearer / Swordtail
Water Type: Freshwater

Natural Range & Habitat:

Wild Xiphophorus hellerii occurs in North and Central America, from the Rio Nantla area of Veracruz, Mexico, through to north-western Honduras. FishBase describes adults as living mainly in rapidly flowing streams and rivers, as well as warm springs, weedy canals and ponds, often in heavily vegetated habitats.

The Kohaku Swordtail is a domesticated aquarium strain, so it should be treated as a captive-bred colour form rather than a wild-type fish.

Appearance & Adult Size:

Kohaku Swordtails usually show a red-and-white body pattern, with colour placement varying naturally between individuals. Some may be mostly white with red patches, while others may carry stronger red coverage across the body and fins. Males develop the long lower-tail extension, or “sword”, that gives the species its name, along with a gonopodium. Females are larger, deeper-bodied and do not develop the same sword.

Adults can reach 10–12 cm in the aquarium, with large females potentially bigger. FishBase lists Xiphophorus hellerii at up to 14 cm for males and 16 cm for females, so this species should be given more space than standard platies.

Aquarium Suitability:

This is a hardy, active livebearer for peaceful community aquariums, planted livebearer setups and larger beginner tanks. Swordtails appreciate open swimming space, plant cover, floating plants and clean, oxygen-rich water. They are more streamlined and active than platies, and Fishkeeper notes that they require a tank at least 3 ft long, preferably longer, because of their adult size and activity.

They are not suitable for very small aquariums, very soft acidic water, aggressive predator tanks or delicate slow-moving communities.

Recommended Aquarium Size:

A practical minimum is 100–120 litres for a small group, with a tank length of at least 90 cm recommended. Larger aquariums are better for mixed-sex groups, multiple males and community setups. FishBase gives a minimum aquarium size of 80 cm, but a longer tank gives better swimming space and reduces male chasing.

Water Conditions:

Temperature: 22–26°C
pH: 7.0–8.2
Hardness: Moderately hard to hard preferred
Additional Notes: Swordtails do best in mineral-rich, neutral to alkaline water. FishBase lists Xiphophorus hellerii at pH 7.0–8.0, hardness 9–19 dH and temperature 22–28°C. Avoid very soft acidic water, poor oxygenation and unstable conditions.

Temperament & Tank Mates:

Aquarium Category: Community Fish

Kohaku Swordtails are peaceful overall, but males can be pushy with each other and persistent with females. Suitable tank mates include platies, mollies in compatible water, peaceful barbs, danios, rainbowfish, bristlenose plecs, Cory-type catfish in suitable water, larger rasboras and other active community fish.

Avoid large predators, aggressive cichlids, slow long-finned fish, very tiny nano fish and species that need soft acidic conditions. Keep in groups, ideally with one male to two or more females if both sexes are kept. Multiple males need enough space and cover to reduce chasing.

Feeding:

Kohaku Swordtails are easy-feeding omnivores. Offer quality flakes, small granules and livebearer pellets 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 wafers, blanched spinach or courgette. FishBase records wild X. hellerii feeding on worms, crustaceans, insects and plant matter, so a varied diet is ideal.

Behaviour in the Aquarium:

This is an active, sociable fish that spends most of its time in the middle and upper levels. Males display with their extended swords and may chase rivals or females, especially in smaller tanks. Females give birth to free-swimming fry rather than laying eggs, and fry may survive in planted aquariums if enough cover is available.

Care Notes:

Keep in a mature, stable aquarium with good mineral content and regular water changes. Provide plants or décor to break up lines of sight, especially when males are present. A secure lid is recommended, as swordtails are strong jumpers. Avoid mixing different Xiphophorus species or colour strains if you want to maintain a pure strain, as swordtails and platies can hybridise in captivity. Fishipedia also warns against mixing similar Xiphophorus species or varieties where hybridisation is a concern.

Recommended For:

Beginner

Availability:

Common to occasional / Captive-bred colour 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, colour, pattern, red coverage, white coverage and tail shape can occur between individual fish.