How difficult is it to keep Small-Eye Medaka?

Advanced. This is an advanced-level species. It requires specialized equipment and advanced husbandry skills with precise environmental control.

What is the ideal temperature for Small-Eye Medaka?

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

What is the lifespan of Small-Eye Medaka?

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

How large does Small-Eye Medaka get?

Small-Eye 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 Small-Eye Medaka?

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

What is the typical price for Small-Eye Medaka?

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

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Small-Eye Medaka

Advanced

Oryzias latipes

An improved medaka whose pupils are greatly reduced, so that weak eyesight leaves it barely able to adjust its colour to the background. It keeps its colour even in a white container, and the trait underpins the black-bodied varieties.

Difficulty

Advanced

Temperature

18〜28℃

Lifespan

2-3 years

Size

Up to about 4cm SL

Diet

Prepared medaka food, green water

About

Small-eye is the trait in which the pupil is greatly reduced, leaving the fish with weak eyesight and therefore little change of colour in response to the background. The Medaka Web Encyclopedia lists it as eye trait 16, explained in line with the Japan Medaka Association classification manual. Medaka normally match their colour to their surroundings, but a small-eye fish cannot read its environment and so keeps a dark body even in a white container. In 2001 Yukio Oba created the pure black medaka, classified as the black small-eye medaka and nicknamed kurobee; because it has since been crossed into the founding stock of today's improved medaka, small-eye can appear from almost any line. Fish with one small eye and one normal eye are called single-sided small-eye; this is not treated as a sub-category of the trait, but such fish are regarded as important in breeding small-eye lines. The encyclopedia records 82 such varieties, and the Japan Medaka Association has certified blue small-eye swallow as new variety No.35 (2018, Yukio Oba).

Source: Wikipedia (CC BY-SA 4.0)

Lifespan of the Small-Eye Medaka

The Small-Eye Medaka lives 2-3 years.

Size of the Small-Eye Medaka

The Small-Eye Medaka grows to Up to about 4cm SL.

Temperature & humidity for the Small-Eye Medaka

The ideal temperature for the Small-Eye Medaka is 18〜28℃.

Basic Info

Origin

Japan (a trait deriving from the pure black medaka, or black small-eye medaka, created in 2001 by Yukio Oba)

Care Specifications

pH: 7–8
Hardness (GH): 9–19 dGH
Water Temp.: 18–28℃

PeacefulGroupBreeding: Hard

Sources: Medaka Web Encyclopedia: Complete Medaka Care Guide / FishBase Oryzias latipes / Medaka Web Encyclopedia: Small eye

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

Small eyeSingle-sided small eyeBlack small eye (pure black, kurobee)

Sources: Japan Medaka Association: Variety Classification Manual, 5th ed. (Sep 2025) / Medaka Web Encyclopedia: Medaka Traits / Medaka Web Encyclopedia: Small eye / Japan Medaka Association: List of Certified New Varieties

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