How difficult is it to keep Deme (Telescope-Eye) Medaka?

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

What is the ideal temperature for Deme (Telescope-Eye) Medaka?

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

What is the lifespan of Deme (Telescope-Eye) Medaka?

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

How large does Deme (Telescope-Eye) Medaka get?

Deme (Telescope-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 Deme (Telescope-Eye) Medaka?

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

What is the typical price for Deme (Telescope-Eye) Medaka?

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

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Deme (Telescope-Eye) Medaka

Intermediate

Oryzias latipes

An improved medaka whose eyes protrude sideways because of a change in the skull, which also shortens the distance from eye to mouth. How far and in which direction the eyes project varies between fish. The trait was found and fixed in 2006 by a breeder named Ono.

Difficulty

Intermediate

Temperature

18〜28℃

Lifespan

2-3 years

Size

Up to about 4cm SL

Diet

Prepared medaka food, green water

About

Deme is the trait in which a change in the skull shortens the distance from the eyes to the mouth and pushes both eyes outward. The Medaka Web Encyclopedia lists it as eye trait 17, explained in line with the Japan Medaka Association classification manual. It was discovered and fixed in 2006 by Mr Ono of Saitama Prefecture, and the degree varies between fish, from eyes projecting sideways to eyes angled upward. Unlike the telescope goldfish the eyeball itself is not enlarged; what marks the fish is the protrusion and the compressed look between eye and mouth. The encyclopedia records 95 varieties carrying the deme trait, including youkihi transparent-scale deme (type No.0549) and white deme big-eye (type No.0668), showing how widely it has been combined with other colours and traits. The Japan Medaka Association has also certified white albino deme see-through as new variety No.10 (2015, Toru Suizu).

Source: Wikipedia (CC BY-SA 4.0)

Lifespan of the Deme (Telescope-Eye) Medaka

The Deme (Telescope-Eye) Medaka lives 2-3 years.

Size of the Deme (Telescope-Eye) Medaka

The Deme (Telescope-Eye) Medaka grows to Up to about 4cm SL.

Temperature & humidity for the Deme (Telescope-Eye) Medaka

The ideal temperature for the Deme (Telescope-Eye) Medaka is 18〜28℃.

Basic Info

Origin

Japan (a trait discovered and fixed in 2006 by Mr Ono of Saitama 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: Deme (telescope 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

Telescope eye (deme)Deme with forward-angled eye (deme memae)Deme with big eye

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