How difficult is it to keep Sailfin Medaka?

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

What is the ideal temperature for Sailfin Medaka?

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

What is the lifespan of Sailfin Medaka?

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

How large does Sailfin Medaka get?

Sailfin 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 Sailfin Medaka?

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

What is the typical price for Sailfin Medaka?

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

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Sailfin Medaka

Intermediate

Oryzias latipes

An improved medaka whose dorsal fin splits into two. It arises when the fin membrane or the fin rays of the dorsal are missing, and tends to appear on the hikari and hikari-daruma body types. The trait was renamed samurai in the 2022 revision of the classification manual.

Difficulty

Intermediate

Temperature

18〜28℃

Lifespan

2-3 years

Size

Up to about 4cm SL

Diet

Prepared medaka food, green water

About

Selfin is the trait in which the dorsal fin becomes two fins, produced when the fin membrane or the fin rays of the dorsal are absent. The Medaka Web Encyclopedia groups it with the fin traits and now writes it as samurai, following the renaming of the trait from selfin to samurai in the 2022 revision of the classification manual. It tends to appear on the hikari and hikari-daruma body types, and the shape of the fins varies from long to narrow. Fish whose anal fin is also doubled are called jouge samurai, and fish with three dorsal fins are called W samurai; both have been recorded. Two other traits also multiply the fins: merah, in which every fin splits according to how much membrane is missing, and choki, in which only the tail of a hikari-type fish divides in two. Selfin affects only the dorsal or anal fin, whereas merah also appears on the standard and daruma body types.

Source: Wikipedia (CC BY-SA 4.0)

Lifespan of the Sailfin Medaka

The Sailfin Medaka lives 2-3 years.

Size of the Sailfin Medaka

The Sailfin Medaka grows to Up to about 4cm SL.

Temperature & humidity for the Sailfin Medaka

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

Basic Info

Origin

Japan (a fin trait defined in the Japan Medaka Association classification manual; renamed samurai in the 2022 revision)

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: Selfin (samurai)

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

Selfin (samurai)Jouge samurai (doubled dorsal and anal fins)W samurai (three dorsal fins)

Sources: Japan Medaka Association: Variety Classification Manual, 5th ed. (Sep 2025) / Medaka Web Encyclopedia: Medaka Traits / Medaka Web Encyclopedia: Selfin (samurai) / Japan Medaka Association: Variety Classification Manual

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