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Karasu Medaka
IntermediateMedaka variety with jet-black body. Darker than Black Diamond lineage, with fins also deeply black being most valued. Appreciated for understated beauty.
Difficulty
Intermediate
Temperature
5〜30℃
Lifespan
2-3 years
Size
3-4cm
Diet
Medaka pellets, daphnia
About
Karasu (crow) medaka is a black-type improved variety bred to pursue a deep crow-like blackness across the whole body. Among black strains it pushes darkness furthest, and individuals black to the very tips of the fins are most prized. Standard body type, roughly 3–4 cm. Black coloration is strongly influenced by environment — it fades easily in white containers, so keeping fish in dark containers deepens and stabilizes the black (a protective color response). Its understated, sober beauty offers a different appeal from brighter varieties and enjoys steady popularity. Peaceful and community-compatible. Selectively breeding the darkest parents maintains the jet-black strain.
Lifespan of the Karasu Medaka
The Karasu Medaka lives 2-3 years.
Size of the Karasu Medaka
The Karasu Medaka grows to 3-4cm.
Temperature & humidity for the Karasu Medaka
The ideal temperature for the Karasu Medaka is 20〜28℃.
Hardy across roughly 5–30°C in neutral to slightly alkaline water.
Basic Info
Origin
Japan (selectively bred variety)
Lifespan
2-3 years
Size
3-4cm
Temperature
Care Specifications
- pH
- 7–8
- Hardness (GH)
- 9–19 dGH
- Water Temp.
- 20–28℃
PeacefulGroupBreeding: Easy
Sources: FishBase: Oryzias latipes / Seriously Fish: Oryzias latipes
Morphs (Varieties)
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.
Other
Black body
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.
References & Sources
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.
Taxonomy & Authority
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 · Japan Medaka Association — Variety Classification Manual (JA)
Nomenclature follows global taxonomic authority databases.
Karasu Medaka Listings
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