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Koi Varieties - Mizuho Ogon

Welcome to another post in our Koi Varieties blog series. Today we are continuing to look at our series of Ogon koi with the Mizuho Ogon. This is a little different to the other Ogon varieties we have already looked at as you will see below.



Mizuho Ogon koi from breeder Hirasawa

The name Ogon koi, as mentioned in our Platinum Ogon blog post (which can be found here), was originally used to refer to the group of all metallic koi. However, as more and more koi varieties were developed, this system became confusing and so Ogon was redefined to mean single-coloured, metallic koi. However, even this can get a little confusing with certain Ogon varieties, one such being the Mizuho Ogon.


The Mizuho Ogon actually appears to be a two-coloured koi as it has a bright red or orange colour similar to the Orenji Ogon but also has a line of black scales along its back. As the koi appears to have two colours, many koi fans don’t automatically recognise it as an Ogon. However, the black is not considered to be an additional skin colour as it is in fact the colour of the reticulation on the scales. The Mizuho Ogon is actually the metallic and Doitsu (scaleless) version of an Aka Matsuba which is a single-coloured red koi with a black net-like reticulation pattern, you can read all about the Aka Matsuba in our Koi Varieties blog:


Since reticulation doesn’t count as a second colour, this means that all metallic Matsuba are also in the group of Ogon koi. So Gin Matsuba and Kin Matsuba koi are Ogons as well as the metallic versions of Aka Matsuba and Shiro Matsuba (which are not yet popular enough to have their own variety names, they are often instead referred to as Kin Aka Matsuba and Kin Shiro Matsuba).


Mizuho Ogon koi from breeder Hirasawa

Little is known about the history of the Mizuho Ogons, all we really know are assumptions! We do know that they were developed after the Aka Matsuba and that the Aka Matsuba came into the koi world in the 1950s. From there, most people believe that the Kin Aka Matsuba was developed with little success. The koi produced were exactly as imagined but unfortunately just did not gain the popularity of other koi varieties being developed at the same time. It is then believed that some of these Kin Aka Matsuba koi were purchased by a different koi farm with the intention of making a Doitsu version as the scaleless koi were very popular in the later half of the 20th Century. All we know for sure about this, however, is that the Mizuho Ogon koi came onto the koi scene in the 1980s from Hirasawa and their popularity only grew from there.


They are, however, still only bred in large numbers in the Hirasawa koi farm and need to be heavily culled due to the large number of judging criteria (for more information, see below), so the variety remains quite a rare and special one. The name ‘Mizuho’ translates as ‘bountiful’ and is often used in Japan to refer to a good harvest or good returns on an investment and that is certainly true of a Mizuho Ogon as they will only continue to grow in quality and value as they age.




Pongoi (Best Quality) Mizuho Ogon Koi


Many people consider Ogon koi to be one of the easiest koi varieties to judge and breed as they are relatively simple with only one colour and no complex patterns. This may be true but it also means that the standards are much higher and little less than perfection is acceptable for the best quality koi. While a small colour bleed or a misaligned scale may be ignored on other varieties, on the clean, unblemished canvas of the Mizuho Ogon, such an imperfection is much more obvious and difficult to ignore. Therefore, most Ogon varieties are judged much more strictly than many other varieties.




Mizuho Ogon koi from breeder Hirasawa (this koi is incredible, the largest we have ever stocked at 72cm!)

When considering the quality of a Mizuho Ogon koi, we need to consider four things. Firstly, the consistency and quality of the colour then, the quality and consistency of the metallic sheen and of the Doitsu scales and finally, the reticulation pattern.


When it comes to judging the base colour of a Mizuho Ogon, we first consider the consistency of the colour. The body should have the same shade along the whole of the koi including the head, fins and tail. As mentioned above, it is often easy to see when there are inconsistencies and blemishes in the colour, and these should be minimised for the best quality Mizuho Ogon. The most important consideration for any Ogon variation is that the koi must have a clean body and ideally also have a clean head, fins, and tail, but the body is most important. Now, with regards to the colour itself, the ideal shade for a Mizuho Ogon is a bright red-orange similar to an autumn leaf or a flame.


The next thing to consider, as we said above, is the metallic sheen on the body of the koi. As with the red-orange base colour, the most important thing about the sheen is that the amount must be consistent over the whole body of the koi and the lustre should have the same quality all over. A koi with poor but consistent lustre is considered better than a koi with both good and bad areas of lustre. The sheen should be visible over all areas of the body with no areas clearly lacking the reflective sheen. For a beautiful metallic koi, the skin should be shiny like a mirror and, on the red-orange base colour of the Mizuho Ogon, be comparable to the lovely red and orange hues of the sun about to set.



Mizuho Ogon koi from breeder Hirasawa

Now, we need to consider the Doitsu scales as this is a Doitsu variety. Because a Doitsu fish has fewer scales than a Wagoi (non-Doitsu) koi, the scales that it does have are much more important. Any imperfection is immediately obvious and makes the whole fish look bad. Each scale should be looked at along the back and checked that each scale is of similar size, either to all of the other scales or to its neighbouring scales, and that no scale is out of place or damaged. It is often acceptable to have a large difference between the largest scale and the smallest scale as long as the size of the scales changes gradually along the spine of the fish. It is very difficult to breed for perfect scales so actually, many breeders aim for fewer scales rather than perfect scales as there is less chance for imperfections with a smaller number of scales!


Finally, we need to consider the reticulation in each of the scales. When a koi has reticulated scales, it means that each scale has a light tint at the base that becomes a darker tint at the top of the scale, resulting in a gradient effect. The colour of this tint varies between varieties, but, typically, the best reticulation occurs when the tint colour is a sharp contrast to the scale and skin colour. For example, in an Aka Matsuba koi, the scales and skin are a deep red and the ideal reticulation colour is a dark grey or black resulting in a strong contrast between the red and the black. This makes the net pattern, or pinecone effect, really stand out on the body of an Aka Matsuba. Since the Mizuho Ogon is the Doitsu version of the Aka Matsuba koi, it should also have the same dark grey or black colour to its reticulation.


Ideally, each scale will have a gradient from grey to a deep, dark black but the darker the top of each scale, the better. Most important, however, is that the colours should be consistent. Every scale should have the same light and dark tints and every scale should have the exact same gradient effect. Any single scale out of place, either with different shades in the reticulation pattern, or in the actual position of the scale, will be very noticeable and is considered a big imperfection in this variety of koi. In fact, when considering any reticulated koi, but especially the Doitsu versions, the most important thing is consistency, each scale should have the same shades and each scale should have the same pattern.



The Mizuho Ogon is a stunning fish but very rare. Any koi pond with a Mizuho Ogon is sure to be special with such an eye-catching variety!


To see our current stock of Mizuho Ogon koi, have a look on our website:


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