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A beautiful variety with deep red color reminiscent of ruby gemstones. Some transparent-scale types show internal organs.
Ruby medaka is an improved variety featuring deep red body color reminiscent of a ruby gemstone, standing alongside Youkihi and Kotei as a representative red medaka. Transparent-scale individuals may show internal organs through the body, adding a mystical quality. Black containers are said to best enhance color expression. High-protein, carotenoid- and astaxanthin-rich color-enhancing food maintains and deepens body color. Hardy in 5–30°C, neutral to slightly alkaline water. Sunlight exposure further deepens the coloration. Selecting the most intensely red parents for breeding increases the proportion of deeply colored offspring.
Origin
Japan (selectively bred variety)
Lifespan
2-4 years
Size
2-4cm
Temperature
5〜30℃(適温20〜28℃)
Artificial feed, Daphnia
色揚げには高タンパク飼料が有効
黒い容器で飼育すると発色が良い
直射日光は色褪せの原因になる
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: (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.
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水温25〜28℃で最も美しい体色に
選別を重ねることで色の固定率が上がる
Intermediate. This is an intermediate-level species. Some prior experience and knowledge of environmental management are recommended.
The ideal temperature for Ruby Medaka is 5〜30℃(適温20〜28℃). Avoid sudden temperature changes and maintain a stable environment.
The average lifespan of Ruby Medaka is 2-4 years. With proper care and nutrition, they can live a long and healthy life.
Ruby Medaka typically reaches 2-4cm as an adult. Size may vary depending on care conditions and individual genetics.
Ruby Medaka feeds on: Artificial feed, Daphnia. Aim for a balanced diet with appropriate feeding frequency.
The price of Ruby Medaka varies significantly depending on morph, size, and lineage. Check our market price page for the latest pricing information.
Last updated: July 8, 2026