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Swallow Medaka
IntermediateOryzias latipes
An improved medaka in which parts of the fin rays protrude so that each fin extends in places. The trait was created in 2012 by Yoshito Tsushima, and the number and length of the extended rays vary widely between individuals.
Difficulty
Intermediate
Temperature
18〜28℃
Lifespan
2-3 years
Size
Up to about 4cm SL
Diet
Prepared medaka food, green water
About
Swallow is not a single variety but a fin-variation trait class in which parts of the fin rays protrude from each fin; the Medaka Web Encyclopedia lists it as the 34th of the recognised traits. It was found and fixed in 2012 by Yoshito Tsushima of Aomori Prefecture, and the name derives from the swallow guppy, which shows a similar kind of fin extension. The Japan Medaka Association classification manual also records the name Fuga for it. Because only part of the rays extends, the number and length of the elongated rays differ greatly between individuals. The similar traits are hirenaga and merah: hirenaga elongates the whole fin including the fin membrane, whereas swallow protrudes only some of the rays. The trait combines with any body colour or body type, so fish are usually named by adding Swallow to an existing variety name; the Medaka Web Encyclopedia cites Kenshin (black swallow hikari) and Shingen as examples built on the trait.
Source: Wikipedia (CC BY-SA 4.0)
Lifespan of the Swallow Medaka
The Swallow Medaka lives 2-3 years.
Size of the Swallow Medaka
The Swallow Medaka grows to Up to about 4cm SL.
Temperature & humidity for the Swallow Medaka
The ideal temperature for the Swallow Medaka is 18〜28℃.
Basic Info
Origin
Japan (trait created in 2012 by Yoshito Tsushima of Aomori Prefecture)
Lifespan
Care Specifications
- pH
- 7–8
- Hardness (GH)
- 9–19 dGH
- Water Temp.
- 18–28℃
PeacefulGroupBreeding: Moderate
Sources: Medaka Web Encyclopedia: Complete Medaka Care Guide / FishBase Oryzias latipes / Medaka Web Encyclopedia: Swallow (Fuga), fin-variation trait 34/44
Morphs (Varieties)
The Japan Medaka Association's classification manual sorts varieties by traits that can be seen rather than by genotype, and does not set out how individual traits are inherited. Traits the manual explicitly says can be passed on and produced by selective, multi-generation breeding are listed as line-bred; the rest are grouped under Other.
Other
Swallow (partial fin-ray protrusion)
Sources: Japan Medaka Association: Variety Classification Manual, 5th ed. (Sep 2025) / Medaka Web Encyclopedia: Medaka Traits / Medaka Web Encyclopedia: Swallow (Fuga), fin-variation trait 34/44
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.
Primary sources
- Wikipedia
- CITES Appendices (species not listed)
- FishBase (IUCN Red List: Least Concern, assessed 2018)
- Medaka Web Encyclopedia: Complete Medaka Care Guide
- Medaka Web Encyclopedia: Swallow (Fuga), fin-variation trait 34/44
- Japan Medaka Association: Variety Classification Manual, 5th ed. (Sep 2025)
- Medaka Web Encyclopedia: Medaka Traits
- FishBase
- GBIF
Taxonomy & Authority
Accepted name: Oryzias latipes (Temminck & Schlegel, 1846)
Breeder: 對馬義人 (2012)
Authority databases: FishBase · GBIF · Medaka Web Encyclopedia: Swallow (Fuga), fin-variation trait 34/44 · Japan Medaka Association: Variety Classification Manual
Nomenclature follows global taxonomic authority databases.
Regulations & Conservation Status
Not CITES-listedIUCN LC · Least Concern
Sources: CITES Appendices (species not listed) / FishBase (IUCN Red List: Least Concern, assessed 2018)
Regulations may change. Always verify the latest information with the relevant authorities.
Swallow Medaka Listings
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