By James Reilly

Part of the mystique of Koi exists in the fact that this unique race of carp developed in one tiny place on the planet. Yet we know that modern common carp have occupied an extensive area of Eurasia for thousands of years. So how did one species of drab, common carp become 13 distinct varieties of Koi with scores of pattern and color variations within those varieties? Is it possible there was a ‘missing link’ in Japan that made for the bridge between common black carp and the colorful Koi carp of today?In this article I would like to explore some facts, historical evidence and theories as to just how the common carp came to be the Nishikigoi of today.

Eras

When Did It Happen?

If we now step back again in time and take a glimpse at the progression of Nishikigoi in the very early days, and specifically focus on the missing link mystery, we see that the story of modern Nishikigoi begins with Asagi. Since all of modern Koi arose from a few unique forms, followed by a concentrated breeding program, the Asagi, as a natural mutation,is a key player in the creation of many varieties. Asagi was present as a recognizable and ‘named variety’ of carp as far back as the Edo period. The most important trait for the purposes of this time line is the fact that the Asagi existed alongside the Matsuba. The Matsuba’s scales are bordered with black, like the wildtype Magoi. But the old Asagi had scales with a border of white. This is an important distinction, as the traits of modern Koi are beginning to emerge with the appearance of Asagi.

By the Meiji period, the Asagi had evolved to the more refined Narumi Asagi form. This is a significantly bluer and lighter-colored Koi that demonstrates a dilution morph, which we will discuss in detail later in this article. The name Narumi Asagi is synonymous with the very popular white, spotted, cotton fabric of that region and of that day. Hopefully, this gives a visual of a very different looking animal when compared to the omnipresent carp of the same region and era.

In a parallel story,the villagers of Niigata (1804-1829) found nature mutations within Magoi stock. These red carp, or Higoi, were concentratedon for 20 years until a scarlet carp was created. It was this stock of mutations that refined and added to modern Asagi, and later lead to the creation of a red and white fish when crossed with yet another mutation. These are perhaps the first real crossings of mutations leading toward a new look. From here, the varieties began to explode in the late Edo and early Meiji period. We not only see modern Asagi as a refinement of mutation, we see Ki Utsuri, Shiro Muji (an improved mutation) and the Sarasa (forerunner of the modern Kohaku and the cross of two mutations).

In the Taisho era we see Shiro Utsuri, modern Kohaku and, of course, Taisho Sansoku, the modern Sanke. During the third year of the Taisho era, early Koi breeders of Higashiyama brought 28 specimens from the mountains to the famous Taisho Exhibition of 1914 to show the world what Koi looked like. In the Showa era we see the emergence of the Showa Sanshoku.

Yet, as well as the selective breedings and line breedings are understood, the early recordsbecome a bit spotty when it comes to the actual period of transition from Magoi varieties to the actual foundation stock used to create the modern Nishikigoi. And, there still seems to be specific genetic details missing in the story of modern Koi origins. Just how could a group of black, brown and blue-gray carp become the brocade fancy carp of the today without an intermediary? What were the missing links that started the process and made this transition possible? And what unique genetic traits did these colored carp mutations contribute that acted as the bridge between the wild carp and the fish described from the Edo era forward?

Typical Mutations

The answer to this question can be found in the natural mutation process appearing in the carp populations of Japan. Carp are a very prolific species, producing thousands of offspring per breeding pair. And the isolated Japanese Magoi populations were typical in that they produced thousands of fry per year within the reservoirs and rice paddies of northwestern Japan. But, unlike other areas and other times in which carp populations existed, the isolated carp populations of that region of Japan were anything but typical. It was in this region that mutation was produced in number, identified and then nurtured by the local villagers.
Some have theorized that the reason such numbers of mutations sprang from this tiny population of isolated food fish was because these mountain regions are subject to strong light in summer and absence of light in winter.

Others suggest the soil of the region contributed to physiological change in the skin of the local carp. Still others suggest that identification of color oddities, and selection of these unique spontaneous forms and the systematic concentration of these like-oddities in limited bodies of water, all contributed to rapid emergence of a number of morphs of the common carp. All this occurred within a very limited geographical region. The Higoi mentioned
previously is one clear example of this.

We may never know or be able to prove one unified theory for just how this small gene pool could have produced a significant number of these missing links, or how long the actual process took. But, fortunately, we can now identify those early mutations based on our modern understanding of common and universal mutations.

It’s All About The Melanin

The first mutations were likely carp of a solid or a mottled white color, pale yellow, jet black or orange, or an orange/ black mottled color. These fundamental morphs are known by zoologists and geneticists to be common among some varieties of the carp family and other lower life forms. In addition, there are some early references to these colors and patterns in early Japanese literature.

In a normal carp, the skin is of a dark, more drab nature, and typically in tones of black, brown or gray.Much of that look is due to a pigment called melanin, which, among many other diverse roles within the skin, acts as protection for skin cells against stress caused by the sun’s ultraviolet rays, as well as oxidative reductive reactions within the skin itself. The phenotype varies based on concentration and location of those color cells containing the melanin.

In a normal individual, this dermal pigment is produced within specialized cells known as melanocytes. In mutated individuals, however, DNA defects in normal skin melanin production cause one of several different changes in the skin and, therefore, the look, or phenotype, of that individual changes dramatically. Perhaps most widely recognized of these phenotypes is the albino.

The true albino is a fish with a complete absence of the ability to produce melanin within their bodies. And, as one might expect, there are degrees of this genetic condition that produce some, less or none of this pigment. Each of these conditions or degrees has a phenotypic mutation than can be passed onto offspring. In some individuals, there is an absence of melanin, as the cells themselves are present but simply cannot produce the pigment for black. In other individuals, the cells are intact, but the ability to synthesize melanin is interrupted along the way, due to blocking of an important biochemical known as tyrosinase. In some individuals, this blocking is partial and, in others, comes back in select areas of the body, such as the tips of scales. Or it returns with age, especially after the fish becomes sexually mature, adding a distinct darkening to what was once a solid colored fish.

Finally, there is another genetic condition where melanin is produced uniformly but in greatly reduced amounts, giving a muted or bluish look to the black skin. It is important to understand that albino Koi are not white Koi. Albino Koi have no black pigment, but they still have other color pigments. So, the typical albino Koi, known as Kigoi, is off-white or pale yellow in appearance.

On the exact opposite end of the spectrum is a genetic defect in which the individual produces excess melanin. This hyper-melanistic condition results in a solid black fish. These fish are true black Koi and should not be confused with wild or food-type Magoi. This mutation is one of the important missing links in the early creation of the Nishikigoi family tree. An example of this group can be seen in Karasugoi.

Is This The Missing Link?

In The End