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Oryzias latipes var.
Medaka where external light spreads across the body like stars. A band of light reminiscent of the Milky Way flows across the body. Premium variety, best viewed from above.
Seiga (Milky Way) medaka is a premium improved variety with external body light spreading extensively across the body, resembling the Milky Way galaxy (seiga means star-river / Milky Way). Developed from Miyuki lineage with particularly wide external body light expression. External light coverage and density are the primary quality criteria; full-body coverage (light uniformly covering from head to tail) is the highest grade, with more uniform illumination indicating higher value. Top-view observation best reveals the fantastical Milky Way-like light band in all its beauty. Hardy in 5–30°C, neutral to slightly alkaline water. Selecting wide-coverage individuals for breeding maintains strong-light lineages. Dark top-viewing containers are optimal for light observation.
Origin
Japan (selectively bred variety)
Lifespan
1-3 years
Size
3-4cm
Temperature
5〜30℃
Medaka pellets, daphnia
Black top-viewing container shows external light most beautifully
Sunlight makes external light shine like stars
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
5-30°C (optimal 20-28°C)
Select by width and density of external light
Fry management affects adult external light quality
Intermediate. This is an intermediate-level species. Some prior experience and knowledge of environmental management are recommended.
The ideal temperature for Seiga Medaka is 5〜30℃. Avoid sudden temperature changes and maintain a stable environment.
The average lifespan of Seiga Medaka is 1-3 years. With proper care and nutrition, they can live a long and healthy life.
Seiga Medaka typically reaches 3-4cm as an adult. Size may vary depending on care conditions and individual genetics.
Seiga Medaka feeds on: Medaka pellets, daphnia. Aim for a balanced diet with appropriate feeding frequency.
The price of Seiga Medaka varies significantly depending on morph, size, and lineage. Check our market price page for the latest pricing information.
Last updated: July 8, 2026