Illustrated Japanese Culture

Nishikigoi: reading the colours of koi

錦鯉

Nishikigoi are ornamental varieties of carp selectively bred for body form, colour, pattern and lustre. Their names describe combinations of visible traits, not separate biological species. Modern koi breeding developed in the mountain villages of Niigata and later became an international activity.

At a modern koi show, visitors examine fish in blue viewing pools.

The former Nijūmuragō area of NiigataBreeding centre

Kōhaku, Taishō Sanshoku and Shōwa SanshokuThree familiar varieties

Body, skin quality, scales and patternLook beyond colour

Carp bred for ornamental traits

Koi come from carp
Goldfish come from crucian carp
Adult size and lifespan require long-term space

Koi and goldfish have different origins

Koi were bred from carp; goldfish were bred from crucian carp. A small koi is therefore not a goldfish. The named koi varieties describe selected ornamental traits within carp, rather than separate species.

Plan for a large, long-lived fish

Koi can live for decades, and some individuals exceed a metre in length. Their eventual size and lifespan vary. Keeping them requires space and water management over many years.

Telling the three familiar varieties apart

Kōhaku: red on white

Kōhaku has a white ground with red markings. It is one of the gosanke, the three especially familiar varieties. The placement and quality of the markings are part of judging, alongside the fish’s body form and condition.

Taishō Sanshoku: red and black markings on white.

Taishō Sanshoku: red and black on white

Taishō Sanshoku, also called Sanke, adds black markings to a white ground with red patterning. Counting three colours is not enough to distinguish it from Shōwa: the ground colour and distribution of black matter.

Shōwa Sanshoku: red and white markings on black.

Shōwa Sanshoku: white and red on black

Shōwa is described as a black-ground fish with red and white markings. Black often appears at the base of the pectoral fins and extends around the body. The gosanke developed across the Meiji, Taishō and early Shōwa periods rather than appearing together at one moment.

Other names describe other features

Utsurimono and Bekko organise black differently

Shiro Utsuri has white markings on a black ground. Bekko varieties have spot-like black markings over a white, red or yellow ground. Ground colour and the arrangement of black help make the distinction.

Doitsu Shōwa combines reduced scaling with Shōwa coloration.

Asagi and Shūsui: a difference in scales

Asagi has a blue-grey, net-like pattern across its scaled back, often with red along the lower sides. Shūsui is a sparsely scaled Doitsu form of Asagi. German food carp with reduced scales were crossed with Japanese ornamental lines, contributing to Doitsu varieties.

Tanchō Kōhaku: a round red marking on the head.

A head marking, a metallic surface or glittering scales

Tanchō describes a round red marking on the head; Ōgon are single-coloured metallic koi; Ginrin describes the sparkling appearance of scales. Pattern, scale type and lustre can combine. They are not three mutually exclusive categories.

Twenty-one basic names in the JAS standard

A 2022 Japanese Agricultural Standard defined 21 basic classification names. Finer distinctions and combinations produce many more named forms, so the standard is not a claim that only 21 kinds of koi exist.

How a local breeding practice developed

Niigata: colour variation in food carp
Retain individuals and choose broodstock
Continue selection among offspring

Colour variations among food carp

About two centuries ago, in the late Edo period, colour variations appeared among carp kept for food in Nijūmuragō, now including Yamakoshi and eastern Ojiya. Breeders selected and crossed fish with unusual colours. Those early coloured carp were the beginning of a continuing breeding process.

The 1914 illustrated register records markings, breeders, sizes and names.

A Tokyo exhibition brings wider attention

Coloured carp exhibited at the 1914 Taishō Exposition in Tokyo drew attention beyond the local area. Ojiya preserves an illustrated record with breeders’ names, sizes and the names then used for the fish, together with a travel-expense account. The drawings show how the fish were recorded at the time.

Koi displayed and sold on the roof of Nihonbashi Takashimaya in the 1930s.

Fish reach a new urban market

Photographs from the 1930s show koi displayed and sold on a Takashimaya department-store rooftop. This is a different setting from the mountain breeding ponds: ornamental carp had become objects of urban display and commerce.

Recovery and a wider market

Winter work in the snowy breeding region in the 1970s.

Breeding resumes after wartime losses

The Second World War disrupted breeding. Surviving parent fish helped breeders rebuild their stocks. A domestic boom developed during roughly 1965–1974, followed by wider interest across Europe, North America and Asia.

Winter keeping also changed

Before indoor wintering ponds became available locally, breeders had to keep koi through Niigata’s snowy winters using other facilities. A photograph from the 1970s shows winter work beside a snow-covered pond. It records an earlier stage of keeping the fish, before today’s facilities became widespread.

Selection is more than copying a pattern

Pair broodstock
Offspring vary
Observe and select as fish grow

Offspring differ from their parents

Breeders pair parent fish and select among their offspring. The young fish do not reproduce a parent’s markings exactly. Repeated selection develops lines with desired combinations of body form, colour, scales and lustre.

Judges look at the whole fish

Evaluation considers body shape, quality, condition and development, as well as pattern. More colours do not automatically make a better koi. An inspection bowl allows the fish’s shape and markings to be viewed clearly from above.

Keeping the fish means managing the water

Pellets: adjust to fish and water temperature

Circulation, filtration and oxygen work together

A pond or tank needs circulation, filtration and oxygen suited to its water volume and stocking. Avoid crowding and overfeeding, prepare chlorinated tap water appropriately, and do not clean filter media with detergent. Clear-looking water alone does not demonstrate good water quality. Watch for changes in activity or feeding, and seek specialist advice if fish appear unwell.

Adjust feeding to the conditions

Water temperature affects feeding. Food left uneaten adds to the waste the system must handle. Observe the fish and conditions rather than assuming one fixed quantity is suitable throughout the year.

Keep ornamental fish out of natural waterways

Escaped or released cultured carp can disturb bottom sediment, reduce aquatic plants and interbreed with local carp. Keep koi within managed waters. Releasing a garden fish into a river or lake can harm the receiving ecosystem.

What can you now explain?

Are koi varieties separate species?

No. Their names describe selected combinations of ornamental traits.

What are the colours of Kōhaku?

Red markings on a white ground.

Why is “three colours” not enough to identify Sanke or Shōwa?

Their ground colour and the distribution of black differ.

How is Shūsui related to Asagi?

It is a sparsely scaled Doitsu form of Asagi.

Can scale type and colour pattern be combined?

Yes. These are different characteristics, not necessarily exclusive categories.

Why was the 1914 Tokyo exhibition important?

It brought the coloured carp of Niigata to a wider audience.

Do young koi copy a parent’s pattern exactly?

No. Offspring vary, and breeders select among them.

Does judging consider only pattern?

No. Body form, quality and condition also matter.

Why is overfeeding a water-management problem?

Uneaten food increases the waste the system must handle.

Why should koi not be released into rivers?

They can disturb habitats and interbreed with local carp.

Sources and images