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