There are currently over one hundred varieties of koi, with new types been actively developed. Each variety has its own colouration and scale type which is used to name and catororise the koi. These varieties are generally divided into 13 recognised classifications.

1. Kohaku

Kohaku are a shiro (white bodied) koi with patches of hi (red markings). The hi can vary between light orange-red and dark red. The pattern of the hi will further distinguish the koi, for example a Kohaku with a zigzag hi pattern is called an Inazuma (lightning strike) Kohaku. Due to their simplicity, Kohaku are probably the most favoured variety of koi, especially in Japan. The Kohaku class was one of the first to become stabilised and bred consistently, in around 1890. One of the most quoted phrases in koi keeping is; “appreciation of koi begins and ends with Kohaku”.

2. Sanke

Taisho Sanshoku, also formally named Taisho Sanke and commonly called Sanke, are a shiro (white) koi with hi (red) which is overlaid with sumi (black) patterns. Basically, a Sanke is a Kohaku with additional sumi markings. Sanke don’t have sumi markings on their head and very rarely below the lateral line. These koi were developed in the Taisho era in Japan and were first exhibited in 1914.

3. Showa

Showa Sanshoku, Showa Sanke, or commonly called Showa, are a karasu (black bodied) koi with hi (red) and shiroji (white) markings. The first Showa was exhibited in 1927, in the Showa period in Japan. During the early periods of their development, Showa displayed a lot of karasu, but modern Showa have been bred to display more shiroji.It can be difficult to distinguish between modern breeds of Showa and Sanke, but Showa will always have their karasu colouration on their heads and below the lateral line.

4. Utsuri

Utsuri, the accepted name for this category is shortened from the formal name of Utsurimono, which literally translates as ‘reflections’ or ‘reflective ones’.

There are three variants of Utsuri which are all a karasu (black bodied) koi with one of either; hi (red), shiroji (white), or ki (yellow) markings.

The Utsuri class became recognised around 1925 as the colourations stabilised. The name Utsurimono was used because the overlaying hi, shiroji, or ki pattern suggests the reflection of colour on the karasu body.

5. Bekko

Bekko translates literally as ‘Tortoise Shell’. Unlike the Utsuri class, which is a colour pattern on a karasu (black bodied) koi, Bekko have a sumi (black) pattern on a coloured base. Koi within the Utsuri and Bekko classes are often confused, but Bekko varieties will always have a clean head with no sumi present. There are three variants of bekko; shiro (white bodied), aka (red bodied), and ki (yellow bodied).

6. Asagi and Shusui

Asagi have a blue-grey colour to the top of their body with a net-like pattern formed from a dark blue edge to each of their scales. Hi (red) is present below the lateral lines and sometimes on the belly and fins. Asagi were one of the first koi variants to be produced, and were documented around 1850. It is from these first Asagi nishikigoi that most of the modern variants were bred.

Shusui, which translates as ‘autumn green’, was created in 1910 by cross-breeding the Asagi with mirror carp.The resulting Shusui is a doitsu version of the Asagi. In some competitions, Shusui are regarded in a classification of their own.

7. Koromo and Goshiki

Koromo, or Goromo, which literally translates as ‘robed’, are a shiro (white bodied) koi with hi (red markings). Koromo were bred from Kohaku and Asagi in the 1950s. The hi on a Koromo has an Asagi-like scale pattern.There are three variants of Koromo;

• Aigoromo, which have an ai (indigo/blue) edge to the scales within the hi pattern,Sumigoromo, which have a sumi (black) pattern to the edges of the scales within the hi pattern, andBudogoromo, whose hi pattern is overlaid with sumi, which gives a budo (grape-like) appearance to the hi pattern.

Goshiki translates as ‘five colours’. These koi were bred from Asagi and Sanke, they have the red, black and white colours of the sanke, which overlays a two-tone asagi, net-like, body colouration.

The Goshiki is a shiro koi which has the Asagi-like pattern overlaid with hi.

The Goshiki Sanke has the same patterns as a Goshiki, with the addition of sumi.

8. Kawarimono

Kawarimono, or Kawarigoi, are formally recognised, non-metallic varieties of koi which don’t fit into any other category. The list of koi varieties which fall into Kawarimono is quite large, and is still growing. Some of the more recognised types are listed below;

• Hajiro are sumi (black bodied) koi with shiroji (white) tips to the tail and fins.

  Hageshiro are similar to Hajiro, but have a shiro head and face.

  Kumonryu (‘Dragon Fish’) is a sumi doitsu koi with swirling shiro markings on its head and body, a pattern which changes shape seasonally.

Some of the singled coloured varieties of Kawarimono are;

• Benigoi (dark-red)
• Kigoi (yellow)
• Soragoi (blue-grey)
• Midorigoi (green)
• Shiro Muji (white)
• and Chagoi (brown/green-brown)

Chagoi and Soragoi have become quite popular due to the belief that these fish grow rapidly and are less skittish that other types of koi. This trait helps to settle and tame other koi in their pond.

Another, fairly recent addition to Kawarimono is Ochiba Shigure. The name translates as ‘fallen leaves’ as the cha (brown) Kohaku-like pattern overlays a sora (blue-gray) body, reminiscent to autumn leaves on water. Like Chagoi and Soragoi, Ochiba Shigure have a reputation for growing quickly and taming easily.

9. Hikarimuji

Hikari translates as ‘shiny’ or metallic’, and muji means ‘single colour’. The koi which fall into the Hikarimuji, or Hikarimono, classification are single coloured koi with a glossy sheen to their skin.Some of the varieties of koi which fall into this class are;

• Orenji (deep-orange) Ogon,
• Aka (red) Matsuba - whose red scales have black centres which give a pinecone effect,
• Yamabuki Ogon - a yellow metallic koi,
• Kin Matsuba - a yellow/gold metallic koi with matsuba patterning,
• and Gin Matsuba - a silver version of the Kin Matsuba.

10. Hikarimoyo

Hikarimoyo are metallic koi, similar to Hikarimuji, but with a pattern consisting of two or more colours. There exception in this group are the metallic versions of Showa and Utsuri - karasu (black bodied) koi with overlaying colours. These fish fall into the Hikari Utsuri Classification.

Some of the varieties of koi in Hikarimoyo are;

• Yamatonishiki - a metallic version of Sanke,
• Hariwake - a white bodied, metallic koi with orange (Orenji Hariwake) or yellow (Yamabuki Hariwake) Kohaku-like markings,
• Sakura Ogon - a metallic Kohaku,
• and Kujaku - which means ‘Peacock’, is a metallic Kohaku with a matsuba (‘pinecone’) pattern.

11. Hikari Utsuri

As mentioned above, Hikari Utsuri are metallic versions of Showa and Utsuri, karasu (black bodied) koi. There are kin (gold) and gin (silver) versions of Hikari Utsuri, depending on the tone of the sheen.

12. Kinginrin

Kinginrin literally means ‘gold and silver scales’. Unlike the Hikari classifications, whose fish have a metallic sheen to their skin, Kinginrin koi have a sparkle effect on many or all of their scales instead. The Kinginrin effect almost resembles finely cracked glass. A Kinginrin koi will display gold and silver sparkles, Kinrin koi only have gold sparkles, and Ginrin only silver. All koi types can be bred with Kinginrin scaled koi, so each variety of koi has Kinginrin specimens.

13. Tancho

The name Tancho comes from the Tancho Crane, the national bird of Japan, which has a red spot on its head, resembling the Japanese flag. For this reason, Tancho koi are very popular.

The Tancho class consists of Kohaku, Sanke or Showa koi who have a single hi (red) spot on their head. For a competition koi to be classed as Tancho, the hi spot must be between the koi’s eyes, not reach as far back as the shoulder and not run down to the nose. Also, there must be no other hi colouration on the koi's body.

Tancho is not a breedable trait, it only ever occurs by chance.

Doitsu

Doitsu koi are Nishikigoi which have been cross-bred with mirror carp. As a result they have either no scales at all, or have scales only along the dorsal and/or lateral lines.Doitsu is not usually considered a classification in it's own right, rather Doitsu Koi fall into categories depending on their colouration (except the Shusui, which is sometimes classed alone). Each colour variety has doitsu specimens.

Non-Nishikigoi Varieties

Further breeding in the latter part of the 20th century has led to developments such as Ghost Koi and Butterfly Koi. These koi are not officially classed as Nishikigoi and, at the moment, can not be entered into tournaments. But, they are still accepted by pond keepers who don’t take koi keeping and breeding too seriously.Ghost Koi are massively popular across the UK. They are a cross breed between metallic Koi and the common carp, are silver or gold, and have a skeletal pattern running down their back.

Butterfly Koi, aslo called Long-fin Koi or Dragon Koi, are nishikigoi which have been cross-bred with the hardier Indonesian longfin carp. As well as inheriting the Indonesian’s resilience and becoming generally hardier than other koi, they have developed a long flowing finnage, longer barbels, and in some fish, pompom nostrils. They are also faster growing than other koi.

Japanese Terms Used for Naming and Describing Koi

Ai - Indigo or blue colouring.

Aka - Red bodied, red base colour.

Akebi - Light blue.

Bekko - “Tortoise shell” (effect).

Beni - Dark red.

Budo - “Grape” (effect), a purple/maroon colouring overlaying hi, likened to the colour of grapes.

Cha - Brown.

Doh - Trunk or body of the fish.

Doitsu - A koi with the scale pattern of a mirror carp.

Gin - Shiny metallic silver effect on the scales.

Goi - Carp.

Gosanke - The collective name for kohaku, sanke and showa.

Hachi - Head.

Hara - Abdominal area.

Hi - Red pattern overlaying the base colour.

Hisocu - Yellow/green.

Hikari - Metallic/Shiny

Inazuma - “Lightning” (effect), zigzag patterning.

Iro - Colour.

Kage - “Shadow” (effect).

Kana - Male koi.

Kao - “Face”.

Karasu - Black bodied, black base colour.

Kawari - “Strange/unfamiliar”

Ki - Yellow.

Kin - Shiny metallic gold effect on the scales.

Konjo - Dark blue.

Koromo - “Robed” (effect).

Koshi - Green.

Kuchibeni - “Lipstick” (effect), hi pattern around the koi’s mouth.

Matsuba - “Pinecone” (effect), the base of the scales have a darker colour than the edges, giving a pinecone effect.

Men - “Face”.

Midori - Green.

Mizu - Light blue.

Mono - One colour or single colouration.

Moyo - More than one colour.

Muji - Single colour.

Namikin - “Tail fin”.

Namitate - “”Dorsal fin”.

Nezu - Grey.

Nishiki - “Brocaded cloth”

Orenji - Orange.

Ozuke - Base of the tail.

Ozutsu - Area behind the dorsal fin.

Rin - “Scales”. Rin is not a single word, it is used in conjunction with other descriptive words, e.g. Ginrin.

Shiro - White.

Shiroji - White colouration of the body or pattern.

Sora - Grey.

Sumi - Black pattern overlaying the base colour.

Tebire - Pectoral fin.

Utsuri - “Reflections”