How difficult is it to keep Tarumi Longfin Medaka?

Intermediate. This is an intermediate-level species. Some prior experience and knowledge of environmental management are recommended.

What is the ideal temperature for Tarumi Longfin Medaka?

The ideal temperature for Tarumi Longfin Medaka is 18〜28℃. Avoid sudden temperature changes and maintain a stable environment.

What is the lifespan of Tarumi Longfin Medaka?

The average lifespan of Tarumi Longfin Medaka is 2-3 years. With proper care and nutrition, they can live a long and healthy life.

How large does Tarumi Longfin Medaka get?

Tarumi Longfin Medaka typically reaches Up to about 4cm SL as an adult. Size may vary depending on care conditions and individual genetics.

What should I feed Tarumi Longfin Medaka?

Tarumi Longfin Medaka feeds on: Prepared medaka food, green water. Aim for a balanced diet with appropriate feeding frequency.

What is the typical price for Tarumi Longfin Medaka?

The price of Tarumi Longfin Medaka varies significantly depending on morph, size, and lineage. Check our market price page for the latest pricing information.

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Tarumi Longfin Medaka

Intermediate

Oryzias latipes

The longfin line of rinkou, the variety carrying net-like external luminescence, in which the extended rays of the dorsal and anal fins branch into a white, feathery mass. Created in 2019 by Masaharu Tarumi, it is the source line for the fusahire trait.

Difficulty

Intermediate

Temperature

18〜28℃

Lifespan

2-3 years

Size

Up to about 4cm SL

Diet

Prepared medaka food, green water

About

Tarumi Longfin is the line name given to rinkou longfin. Rinkou is an improved medaka whose external luminescence reads as a mesh because the sheen enters each individual scale; it was created in 2019 by Masaharu Tarumi, and its longfin form is registered in the Medaka Web Encyclopedia as type No.0207, variety No.0192, under the classification name yellow-blue translucent-scale external-luminescence longfin medaka. Longfin is the trait in which the rays of the dorsal and anal fins extend across the whole fin, and rinkou was already known for a strong fin sheen that produced longfin individuals. The encyclopedia calls the white, feathery effect that arises when the rays of an extended fin branch and guanine gathers there fusahire, and states that this trait was created in 2019 by Masaharu Tarumi of Ehime Prefecture and circulated under the line name Tarumi Longfin. Crossing that line with morpho later strengthened the fusahire expression and raised its heritability, and the pairing was named Marriage Longfin after how well the two went together. Every variety in the Marriage group traces back to this line.

Source: Wikipedia (CC BY-SA 4.0)

Lifespan of the Tarumi Longfin Medaka

The Tarumi Longfin Medaka lives 2-3 years.

Size of the Tarumi Longfin Medaka

The Tarumi Longfin Medaka grows to Up to about 4cm SL.

Temperature & humidity for the Tarumi Longfin Medaka

The ideal temperature for the Tarumi Longfin Medaka is 18〜28℃.

Basic Info

Origin

Japan (line created in 2019 by Masaharu Tarumi of Ehime Prefecture)

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 No.0207 (Rinkou Longfin) / Medaka Web Encyclopedia No.0831 (Marriage Longfin)

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

Yellow body colourBlue body colourTranslucent scales (aurora)External luminescence (rinkou, net-like)Longfin (dorsal and anal fin-ray extension)Fusahire (branching, feathery fin rays)

Sources: Japan Medaka Association: Variety Classification Manual, 5th ed. (Sep 2025) / Medaka Web Encyclopedia: Medaka Traits / Medaka Web Encyclopedia No.0207 (Rinkou Longfin) / Medaka Web Encyclopedia No.0831 (Marriage Longfin)

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

Taxonomy & Authority

Accepted name: Oryzias latipes (Temminck & Schlegel, 1846)

Breeder: 垂水政治 (2019)

Authority databases: FishBase · GBIF · Medaka Web Encyclopedia No.0207 (Rinkou Longfin) · Medaka Web Encyclopedia No.0831 (Marriage Longfin) · Medaka Web Encyclopedia No.0206 (Rinkou)

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.

Tarumi Longfin Medaka Listings

Find listings for this species

🩺 Common diseases

About

Source: Wikipedia (CC BY-SA 4.0)

Morphs (Varieties)

Other

Yellow body colourBlue body colourTranslucent scales (aurora)External luminescence (rinkou, net-like)Longfin (dorsal and anal fin-ray extension)Fusahire (branching, feathery fin rays)

A curated selection of notable morphs. Inheritance modes are a breeding-planning guide; actual appearance varies with combos.

Care Guide

Lighting

The net-like sheen appears on the back and suits viewing from above, while the white, feathery fins read best from the side at an angle. Outdoors, summer sun raises water temperature sharply, so shade half the container with something such as a reed screen.

Diet & Nutrition

Commercial prepared medaka food is the staple, given in an amount finished within a few minutes. Leftovers decay and foul the water, so adjust the quantity. Green water rich in phytoplankton suits fry rearing.

Water Temperature & Quality

Slightly acidic to slightly alkaline water is considered ideal, and the water drifts toward acidic as keeping continues. Around one water change per week is the guideline, and because sudden shifts in temperature or pH cause stress, acclimatise new fish by floating the bag. FishBase records the wild water chemistry of this species as pH 7.0-8.0 and hardness 9-19 dH.

Tank Mates & Compatibility

Elongated fins are easily damaged by obstructions or crowding, so keep the container uncluttered and the stocking light. A peaceful schooling fish, normally kept as a group of the same variety. One litre of water per fish is the guideline against overcrowding; overstocking causes poor growth, reduced breeding, oxygen shortage and water fouling.

Breeding

The Medaka Web Encyclopedia states that crossing this line with morpho to make Marriage Longfin both strengthened the fusahire expression and raised its heritability. Outdoors the spawning season runs from about April to October, once water reaches 18C or above with 12-13 hours of daylight. For year-round indoor breeding, 25-28C water and over 13 hours of lighting are the guideline. Eggs hatch at a cumulative 250 degree-days, about 10 days at 25C.

Health & Notes

The Medaka Web Encyclopedia describes Marriage Longfin, bred from this line, as a fish whose finish depends on its environment. Generous stocking room and a steady water temperature are the guideline for drawing out the fusahire expression. The extended, branching fins damage easily, so keep the container uncluttered. Outdoors the fish become inactive and overwinter near the bottom as water cools, resuming activity in spring once daytime water exceeds 10C. A 0.3-0.5% salt bath is used for ailing fish, with water raised to no more than about 28C.

Tarumi Longfin Medaka

About

Lifespan of the Tarumi Longfin Medaka

Size of the Tarumi Longfin Medaka

Temperature & humidity for the Tarumi Longfin Medaka

Basic Info

Care Specifications

Morphs (Varieties)

References & Sources

Taxonomy & Authority

Regulations & Conservation Status

Tarumi Longfin Medaka Listings

Related Articles

🩺 Common diseases

For Breeders

Tarumi Longfin Medaka

About

Lifespan of the Tarumi Longfin Medaka

Size of the Tarumi Longfin Medaka

Temperature & humidity for the Tarumi Longfin Medaka

Basic Info

Care Specifications

Morphs (Varieties)

References & Sources

Taxonomy & Authority

Regulations & Conservation Status

Tarumi Longfin Medaka Listings

Related Articles

🩺 Common diseases

Diet