Koi Varieties – The Ultimate Guide

At Keruto Koi, we stock a great number of koi of different varieties, and we appreciate that the koi keeping hobby can be very difficult for everyone, newcomers and even experienced koi keepers alike, with the amount of information available and the number of different varieties to choose from. To help understand the different koi varieties that are available here at Keruto Koi, we have put together this Ultimate Guide containing useful information on all of the most popular koi varieties, and some more unusual varieties as well!

What are koi carp?

Koi fish are a very popular species of carp that have been bred and kept as ornamental fish for hundreds of years. The koi keeping hobby dates back as far as 200BC when the Magoi carp (meaning ‘common carp’) was brought to Japan from China. The Magoi carp was originally bred as a food source, but people quickly started keeping them as pets once skin colour mutations began appearing naturally. It wasn’t until the late 19th century and early 20th century, however, that koi keeping became a popular hobby. Until then, only the richest aristocrats and royalty kept the Magoi carp as ornamental pets rather than eating them.

The koi keeping hobby as we know it started with the Asagi koi which was first recognised as an ornamental carp around 160 years ago. This koi was often kept by the carp farmers due to its interesting patterns and prompted the popularity of the hobby which led to all sorts of people keeping carp fish, not just the upper class. Shortly after the Asagi had become popular, other mutations in the carp began popping up and farmers began to keep more and more different carp fish.

Of course, at this point, the farmers decided to give these fish a different name to differentiate the pet Magoi carp from the Magoi carp for eating. Thus, the ornamental carp were named ‘Nishikigoi’ which literally translates as ‘swimming jewel’ and basically means beautiful fish. Over time, with more and more people joining the hobby, the word was shortened to ‘koi’ which is the commonly used word nowadays.

About this guide

This guide contains information about a great number of different koi varieties. Use the links at the top to jump to different parts of the page. Under each variety is some brief information about the variety and its history, a picture of a Pongoi (best quality) koi of the variety and a pronunciation guide. You will also find links to our ‘Koi Varieties’ blog post for each variety where you can read more about it and a link to the ‘For Sale’ page where you can view our current stock of each variety.



Aka Matsuba

Aka Matsuba koi from breeder Aokiya

Matsuba koi are a subvariety of koi that are all single-coloured koi with a black net-like reticulation pattern, some Matsuba varieties, such as Gin Matsuba and Kin Matsuba, are metallic koi while other Matsuba varieties, such as Ki Matsuba and Shiro Matsuba are non-metallic koi. The Aka Matsuba koi is the red, non-metallic version of the subvariety.

The word Matsubagoi (MAHT-soo-BAH-goy) translates as ‘pine needles’ and refers to the pinecone-effect seen on a koi when it has reticulated scales. Reticulation means that the scales themselves have a tint to them, resulting in a strong contrast between the skin colour of the koi and the tint colour on the scales. This pattern gives the koi a net-like appearance or a pine-cone appearance. Matsubagoi technically refers to any reticulated koi but is usually only used when talking about a single-coloured reticulated koi. For such fish, we usually add a prefix, such as Aka, to describe the colour of the koi and shorten ‘Matsubagoi’ to ‘Matsuba’.

All Matsuba koi were created in some way from the Asagi variety, which is a blue koi with strong reticulated scales and a hi (red) pattern along the sides of the body. The Aka Matsuba was created from a pairing of a high-red Kohaku (white fish with red markings, the high-red means it is a mostly red Kohaku) and a Hi Asagi (variation of Asagi koi with more red colouration than normal) in the late 1950s. This pairing resulted in a wide range of fry, mostly with reticulation but some without, and a wide range of colours, with blues, whites, and reds visible across the generation. The few fry that had only red colouration were the koi that, with a little refinement, would soon become the Aka Matsuba variety with strong red colouration from the Hi Asagi koi and the Kohaku koi and a good quality reticulation from the Asagi koi.

Things to consider when judging this variety:

· Hi (red) base colour

· Reticulation pattern



Asagi koi from breeder Oya

Asagi (ah-SAH-gee) are grey-blue koi with reticulation in the scales and red colouration along the sides of the fish, and the fins. These koi are typically quite subdued, and calm compared to other varieties of koi, and it is because of this, as well as the fact that they are such an established variety, that the Asagi variety is very commonly seen in many ponds.

Many koi keepers argue that Asagi is the greatest variety of koi because it was the first recognized ornamental carp, that is, the first koi variety. The ancestor fish of koi carp is the Magoi (mah-GOY) wild carp which was a staple food in many Japanese diets for hundreds of years before the first koi came to be. The Magoi black carp was first brought to Japan in roughly 200BC by an invading force from China.

It was not until about 160 years ago when Magoi farmers decided to breed the fish as ornamental fish. At that point, they had been farming Magoi for over 2000 years since it was introduced to Japan. Before then, the occasional Magoi had been born with mutations causing colour changes in the skin and scales, but the farmers considered these to be defects. Therefore, the fish were removed from the gene pool so that these defects would not continue to be present. However, some farmers decided to keep these fish as trophies and as "collectors’ fish" as they looked different and more interesting than the standard Magoi. This then led to local farmers sharing their "defective" Magois and competing with each other over who has the best fish. As you can imagine, the farmers then decided to start breeding these Magoi so as to get more mutations that could be shown off. These farmers were in fact the first koi breeders.

It did not take many generations of these mutated Magois before the typical pattern that is associated with modern Asagi started to crop up. Once this pattern started to become popular, so did the practice of keeping these fish as pets. More and more people wanted them, and not all farmers. Thus begin the market for Asagi fish and with it came the hobby of koi keeping.

Things to consider when judging this variety:

· Clean head

· Amime scale reticulation pattern

· Hi (red) pattern

· Kiwa (edges) of colours




Benigoi koi from breeder Hirasawa

Benigoi (BEN-ee-GOY) koi are non-metallic, solid red or orange koi fish. The name Benigoi literally translates as ‘red koi’. You may have noticed that, in the koi keeping hobby, there are a few different Japanese terms meaning ‘red’, the most common of which is ‘hi’. This koi variety is called ‘Benigoi’ rather than ‘Higoi’ because the ideal colour of the koi is an orange-red associated with the word ‘beni’, rather than the deep, fiery red associated with the word ‘hi’, such as on a Kohaku koi.

The Benigoi koi variety was one of the original koi varieties, first popularised in the early 1920s. The variety began with the Magoi carp which was a black wild carp common in Japan in the 18th and 19th centuries. Around the beginning of the 19th century, wild carp started to become pets rather than purely food and koi keeping started to become a hobby. Many of the early koi varieties came about as a variation or a mutation of the wild carp and the Benigoi is no exception. In fact, the very first variation of the wild carp seen by the carp farmers was the red-bellied Magoi. By selectively breeding pairs of wild Magoi that each have small amounts of red colouration on their underside, farmers were able to produce a Magoi with a purely red belly – the appropriately named red-bellied Magoi! This red-bellied Magoi was then bred with the Kohaku koi (a white koi with a red pattern) to produce a pure red fish, the Benigoi.

Things to consider when judging this variety:

· Beni (red) colouration

· Fukurin reticulation pattern




Chagoi koi from breeder Yamazaki

The Chagoi (CHAH-goy) koi, literally translating to ‘brown carp’ are an old variety of koi that look very similar to the wild carp. They are typically referred to as the ’gentle giant’ as they tend to grow much bigger than other koi varieties and are very docile around people. They will typically come and greet you at the top of the pond, be willing to be touched, and will often encourage other koi in the pond to be more friendly.

Chagoi koi were first bred in the Taisho Era (the period from 1912 to 1926 when Emperor Taisho controlled Japan). These koi were different from the many other varieties of ornamental carp as they were not bred specifically to create a variety of koi, or for a particular colour, pattern or even skin type. Instead, Chagoi were created accidentally from selectively breeding traits in the common carp that made them more valuable as food and easier to keep. That is, they bred the fish to be big as well as tame and friendly. With each new generation of Magoi (common carp), the farmers chose to grow on and breed only the biggest, friendliest fish and within only a few generations, the majority of fish born were lovely and tame. At this point, their colours had changed a little and they were significantly different from the wild Magoi in both size and temperament that they were often kept as pets and even sold as pets rather than as food. It was at this point that the variety was formally named the Chagoi.

As the years passed and more varieties were developed, it became clear that the breeding methods used to stabilise the varieties were having a negative effect on the size of the koi and the rate of growth. Koi that were significantly different from the wild koi, such as Doitsu koi, typically grew a lot slower and rarely reached the same size as Chagoi koi. Even today, almost all the prizes for the largest koi go to Chagoi koi and the variety has the largest percentage of Jumbo koi (koi from a good bloodline of larger fish).

Things to consider when judging this variety:

· Cha (brown) colouration

· Fukurin reticulation pattern




Ginga koi from breeder Aokiya

The Ginga (geen-GAH) koi is the Wagoi (meaning non-Doitsu) version of a Kumonryu. So, a Ginga koi is a scaled, metallic white koi with a shifting black pattern.

The word Ginga translates as ‘Milky Way’ and was chosen as the patterns and scales of the Ginga koi look like the Milky Way and the stars we can see at night. It was also chosen to reference the constantly changing sumi (black) pattern since the star’s positions are constantly changing as they move around the sky depending on the season and time of year.

The Kumonryu koi shot to popularity shortly after it was introduced to the hobby and has fascinated many koi keepers and breeders. Following on from this popularity, the Ginga koi was created as a fully scaled variation of the Kumonryu but quickly became its own variety. The Ginga koi was created from a pairing of a Kumonryu koi and a Matsukawabake koi which is a non-metallic, scaled white koi with a constantly changing black pattern. That is, the Matsukawabake is the scaled version of a Kikokuryu. This pairing gave the Ginga koi the colours and patterns found in both parent varieties as well as the Wagoi (normal) scales from the Matsukawabake and the metallic skin from the Kikokuryu.

As with both the Kumonryu and Kikokuryu koi discussed before, the sumi pattern of the Ginga koi is constantly changing. It is not certain yet exactly what is causing the pattern to change but changes have been observed in individual fish from changing the water conditions, temperature, diet, stress levels, pH, and many other variables. For some koi, the change will be very gradual and very minimal. For others, the change can be very quick and very drastic. For still others, it can be anything in between. One thing is for sure – the changes in each individual Ginga koi make it a very interesting variety to own and watch as you never know what to expect when you look into your pond!

Things to consider when judging this variety:

· Shiro (white) base colour

· Sumi (black) colour quality

· Metallic lustre and sheen


Gin Matsuba

Gin Matsuba koi from breeder Oofuchi

The term Gin Matsuba (GEEN maht-SOO-bah) translates as ‘silver pinecone’ and describes exactly what this fish looks like! A Gin Matsuba koi is a metallic shiro (white) koi with deep, dark reticulation in the scales. The metallic shiro gives the fish a silvery appearance while the reticulation gives the Matsuba variety its recognisable pinecone, or net-like, appearance.

The Gin Matsuba koi first became known to the koi keeping hobby in the 1960s when an Asagi koi (a blue koi with dark reticulation and a red pattern along the sides of the fish) was bred together with a Platinum Ogon koi (a metallic single-coloured, white koi). This resulted in the Gin Matsuba koi which has the appearance of a Platinum Ogon koi but with the addition of the reticulated scales from the Asagi koi.

In fact, when Gin Matsuba koi are young, as with many other koi varieties, the darker colours take longer to develop and appear. This means that young Gin Matsuba koi usually do not have visible reticulation and are therefore often mistaken for Platinum Ogon koi. With some Gin Matsuba, a slight blue tinge can be seen which is the reticulation underneath the skin, waiting to co