Big-Eye Medaka
IntermediateOryzias latipes
Not a single variety name but a fin trait: a broad caudal peduncle and dorsal and anal fins with extra rays that extend lengthwise. It originated in Kitatsuji Hire-Long.
Wide fin is not a single variety but one of the fin traits defined in the Japan Medaka Association classification manual. According to the Kairyo Medaka Web Zukan, Kenji Yamamoto found a male with this feature in 2016: the caudal peduncle is broad and the dorsal and anal fins carry extra rays, so the fins extend lengthwise. Fish with this trait were registered as JMA new variety No. 36, Kitatsuji Hire-Long, in 2021, and the feature was later classified as the 'wide fin' trait. Many varieties now combine it with other colours or long fins, and wide-fin entries are common at shows. A name containing 'wide fin' says nothing about body colour or scales, so check the full variety name. It differs from hire-naga (long fin), in which fin rays lengthen.
Source: Wikipedia (CC BY-SA 4.0)
The Wide-Fin Medaka lives 2-3 years.
The Wide-Fin Medaka grows to About 3-4 cm (wild medaka reach up to 4 cm SL: FishBase).
Origin
Japan (ornamental cultivar)
Lifespan
2-3 years
Size
About 3-4 cm (wild medaka reach up to 4 cm SL: FishBase)
Temperature
5〜30℃
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 (Temminck & Schlegel, 1846)
Synonyms: Aplocheilus latipes (Temminck & Schlegel, 1846), Poecilia latipes Temminck & Schlegel, 1846
Authority databases: GBIF · GBIF · 日本メダカ協会 品種分類マニュアル
Nomenclature follows global taxonomic authority databases.
Ornamental medaka are cultivars of Oryzias latipes. Not listed in the CITES Appendices (checked on Species+) and not regulated under Japan's Invasive Alien Species Act. Japan's wild medaka (Oryzias latipes and O. sakaizumii) are listed as Vulnerable on the Ministry of the Environment Red List and differ genetically by region. Releasing ornamental medaka into rivers, ponds or rice paddies causes genetic pollution through hybridisation with wild fish, so never release them.
Sources: Species+ (CITES) / Ministry of the Environment: list of invasive alien species / Wikipedia (Japanese): Medaka – conservation and genetic pollution
Regulations may change. Always verify the latest information with the relevant authorities.
Find listings for this species
Omnivore (floating prepared foods, live foods such as daphnia)
Wide fins are best seen from the side in a glass tank; avoid sharp décor.
Expression varies by variety and line; choose breeders with long dorsal and anal fins and a thick caudal peduncle.
Peaceful and fine with other medaka of similar size. To keep the variety's traits, do not let it breed with other varieties in the same container.
Give floating food that is eaten within 3-5 minutes: at least twice a day in summer, once a day in spring and autumn, and little or none outdoors in winter.
Never release ornamental medaka into rivers, ponds or paddies; hybridisation causes genetic pollution of wild medaka.
Intermediate. This is an intermediate-level species. Some prior experience and knowledge of environmental management are recommended.
The average lifespan of Wide-Fin Medaka is 2-3 years. With proper care and nutrition, they can live a long and healthy life.
Wide-Fin Medaka typically reaches About 3-4 cm (wild medaka reach up to 4 cm SL: FishBase) as an adult. Size may vary depending on care conditions and individual genetics.
Wide-Fin Medaka feeds on: Omnivore (floating prepared foods, live foods such as daphnia). Aim for a balanced diet with appropriate feeding frequency.
The price of Wide-Fin Medaka varies significantly depending on morph, size, and lineage. Check our market price page for the latest pricing information.
Last updated: September 23, 2026
