Kouhaku Medaka
IntermediateOryzias latipes
A line of kohaku medaka with normal (non-transparent) scales, prized for the whiteness of its white ground that sets off the red. Body shine was used in its ancestry, so shine and lamé offspring appear.
Komachi is one trade name of the white-and-orange-red medaka, also called non-transparent-scale kohaku; the Kairyo Medaka Web Zukan credits it to Kunio Ono, 2018. Whereas kohaku and three-colour breeders often focus on the coloured areas, Komachi emphasises the pure white ground that makes the red stand out, and that whiteness is its key feature. Unlike transparent-scale kohaku, its gill covers do not look red. Because body-shine fish were used in its ancestry, shine and lamé fish can appear even from Komachi x Komachi. It differs from Amaterasu, another kohaku, by lacking scale shine.
Source: Wikipedia (CC BY-SA 4.0)
The Komachi Medaka grows to About 3-4 cm (wild medaka reach up to 4 cm SL: FishBase).
Origin
Japan (ornamental cultivar)
Lifespan
Few reliable data
Size
About 3-4 cm (wild medaka reach up to 4 cm SL: FishBase)
Temperature
5〜30℃
Omnivore (floating prepared foods, live foods such as daphnia)
Edited & verified by: BreederDirect editorial team
The taxonomic, regulatory, and husbandry data on this page are compiled and verified against the authoritative primary sources below.
Accepted name: Oryzias latipes (Temminck & Schlegel, 1846)
Synonyms: Aplocheilus latipes (Temminck & Schlegel, 1846), Poecilia latipes Temminck & Schlegel, 1846
Authority databases: GBIF · GBIF · 日本メダカ協会 品種分類マニュアル
Nomenclature follows global taxonomic authority databases.
Ornamental medaka are cultivars of Oryzias latipes. Not listed in the CITES Appendices (checked on Species+) and not regulated under Japan's Invasive Alien Species Act. Japan's wild medaka (Oryzias latipes and O. sakaizumii) are listed as Vulnerable on the Ministry of the Environment Red List and differ genetically by region. Releasing ornamental medaka into rivers, ponds or rice paddies causes genetic pollution through hybridisation with wild fish, so never release them.
Sources: Species+ (CITES) / Ministry of the Environment: list of invasive alien species / Wikipedia (Japanese): Medaka – conservation and genetic pollution
Regulations may change. Always verify the latest information with the relevant authorities.
Find listings for this species
Top view shows the white ground best; fish with a sharp boundary between red and white are the most striking.
Kohaku patterns vary among siblings; choose breeders with a clean white ground. Shine or lamé fish may appear.
Peaceful and fine with other medaka of similar size. To keep the variety's traits, do not let it breed with other varieties in the same container.
Give floating food that is eaten within 3-5 minutes: at least twice a day in summer, once a day in spring and autumn, and little or none outdoors in winter.
Never release ornamental medaka into rivers, ponds or paddies; hybridisation causes genetic pollution of wild medaka.
Beginner. This is a beginner-friendly species. No special equipment or experience is required, and it can be kept successfully with basic care setup.
Komachi Medaka typically reaches About 3-4 cm (wild medaka reach up to 4 cm SL: FishBase) as an adult. Size may vary depending on care conditions and individual genetics.
Komachi Medaka feeds on: Omnivore (floating prepared foods, live foods such as daphnia). Aim for a balanced diet with appropriate feeding frequency.
The price of Komachi Medaka varies significantly depending on morph, size, and lineage. Check our market price page for the latest pricing information.
Last updated: September 28, 2026
