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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. Selecting wide-coverage individuals for breeding maintains strong-light lineages. Dark top-viewing containers are optimal for light observation.
The Seiga Medaka lives 2-3 years.
The Seiga Medaka grows to 3-4cm.
The ideal temperature for the Seiga Medaka is 20〜28℃.
Hardy in 5–30°C, neutral to slightly alkaline water.
Origin
Japan (selectively bred variety)
Lifespan
2-3 years
Size
3-4cm
Temperature
Sources: FishBase: Oryzias latipes / Seriously Fish: Oryzias latipes
Selectively bred killifish are trait combinations of body form × body color × pattern × luminescence (internal/external) × scale types (transparent scales) × sparkle × fin morphology and so forth. Published entries include only confirmed traits constituting the given variety, with genetic inheritance patterns provided only for confirmed traits (uncertain cases omitted). Genetic patterns are provided as reference for breeding.
Sources: JMA Japan Medaka Association — Improved Medaka Variety Classification Manual (JA) / Improved Medaka Web Encyclopedia (medakazukan, JA)
A curated selection of notable morphs. Inheritance modes are a breeding-planning guide; actual appearance varies with combos.
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 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 · Japan Medaka Association — Variety Classification Manual (JA)
Nomenclature follows global taxonomic authority databases.
Find listings for this species
5〜30℃
Medaka pellets, daphnia
Black top-viewing container shows external light most beautifully
Sunlight makes external light shine like stars
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 20〜28℃. Avoid sudden temperature changes and maintain a stable environment.
The average lifespan of Seiga Medaka is 2-3 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: August 31, 2026