
AI-generated image
Oryzias latipes var.
Red and white bicolor medaka like Kohaku koi. Each individual has unique markings. Color fixation is challenging, making selection deeply rewarding.
Kouhaku medaka reproduces the Kohaku koi pattern (red markings on white base) in medaka form, popular as 'swimming miniature koi.' Each individual has completely unique red-white ratio, placement, and pattern shape — no two fish are alike. Fixation rate is low, requiring mass breeding and strict selection of ideally distributed red-white patterns to maintain quality. White containers with top-view observation best reveal the red-white contrast. Carotenoid-containing food helps maintain red coloration. Hardy in 5–30°C, neutral to slightly alkaline water. Strong breeding instinct with spawning mats produces large numbers of offspring for selection.
Origin
Japan (selectively bred variety)
Lifespan
1-3 years
Size
3-4cm
Temperature
5〜30℃
Medaka pellets, daphnia
White containers show red-white pattern clearly
5-30°C (optimal 20-28°C)
Pattern changes as fish grows
Sources: FishBase: Oryzias latipes / Seriously Fish: Oryzias latipes
改良メダカは体型×体色×柄×光(体内/体外)×鱗(透明鱗)×ラメ×ヒレ等のトレイト合成。掲載は当該品種を構成する確証トレイトのみで遺伝形式は確証のみ付与(不確実は省略)。遺伝形式は交配の参考。
Sources: JMA日本メダカ協会 改良メダカ品種分類マニュアル / 改良メダカWEB図鑑(medakazukan)
A curated selection of notable morphs. Inheritance modes are a breeding-planning guide; actual appearance varies with combos.
Edited & verified by: br-choku 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 var. (Temminck & Schlegel, 1846)
Synonyms: Aplocheilus latipes (Temminck & Schlegel, 1846), Poecilia latipes Temminck & Schlegel, 1846, Oryzias latipes latipes (Temminck & Schlegel, 1846)
Authority databases: FishBase · GBIF · 日本メダカ協会 品種分類マニュアル
Nomenclature follows global taxonomic authority databases.
Find listings for this species
Pattern fixation rate is low — mass breeding and selection needed
Achieving ideal pattern requires multiple generations
Intermediate. This is an intermediate-level species. Some prior experience and knowledge of environmental management are recommended.
The ideal temperature for Kouhaku Medaka is 5〜30℃. Avoid sudden temperature changes and maintain a stable environment.
The average lifespan of Kouhaku Medaka is 1-3 years. With proper care and nutrition, they can live a long and healthy life.
Kouhaku Medaka typically reaches 3-4cm as an adult. Size may vary depending on care conditions and individual genetics.
Kouhaku Medaka feeds on: Medaka pellets, daphnia. Aim for a balanced diet with appropriate feeding frequency.
The price of Kouhaku Medaka varies significantly depending on morph, size, and lineage. Check our market price page for the latest pricing information.
Last updated: July 8, 2026