When Japanese words enter the English language, they tend to be used in a context that recalls their origins. Thus, many people are familiar with kimonos, sushi, Zen, bonsai, rickshaws and manga, and each of these carries the strong stamp of Japanese culture. But there are of course exceptions, as evidenced by such terms as “tsunami,” “karaoke” and “tycoon,” which now enjoy a linguistic existence completely independent of their etymological basis. And it is to this latter category that “koi” belongs.
Koi tend not to be known simply as such in English, but are more commonly called koi fish or koi carp. However, since “koi” in Japanese simply means “carp”—all kinds of carp—the latter English expression does amount to saying “carp carp.”
However “koi” is modified in English, the term is used to refer to the large ornamental fish in usually variegated colors that are commonly known as nishikigoi (brocaded carp) in Japanese. Since these fish are bred expressly for the decorative purpose of looking handsome as they glide around a pond, they are fortunate in that they never end up looking handsome on a plate.
The breeding of carp as food fish dates back millennia and was practiced in different countries. But the selective breeding of carp to enhance color mutations began in China over a thousand years ago, and the result was the goldfish—now considered a separate species to the Prussian carp from which it derived. By contrast, koi were developed from common carp in the Japanese prefecture of Niigata in the early nineteenth century. Farmers originally bred them as food fish, but when natural mutations resulted in distinctive markings, the farmers decided that it would be a pity to put such specimens to the knife, and the breeding of decorative carp began. By the twentieth century, a number of color patterns had become established, by which time koi had spread beyond Niigata Prefecture and were gracing waters around the nation.
From those small beginnings, koi have become big business. And recent decades have seen that business take on an increasingly international character. Hundreds of professional breeders compete in Japan, and dozens more raise the fish in many countries around the world. Specialist companies sell the filtration equipment, feed and other necessities to ensure that the carp in the pond is a contented fish. As the hobby has grown, so have the prices: top fish pass hands for many tens of thousands of dollars.
Unlike goldfish, which do not do a great deal except flit around the bowl, koi are interactive creatures, and they develop their own personalities like cats and dogs. Koi learn to recognize their owners and will swim to the pond’s edge to greet them. Older fish will eat directly from a person’s hand and gladly accept anything from watermelon and peas to chicken eggs. In addition to gardens, koi are a familiar sight in Japan in such places as old castle moats and ponds in public parks. At the more popular spots, the eagerness of people to feed the creatures is evident in the size of the fish, which sport girths the size of small tree trunks and present cavernous maws in anticipation of food from passers-by.
Koi are classified by their colors and patterns. The most common and prized are kohaku, which are white fish with red spots. Like the Japanese crane after which they are named, tancho kohaku are white with a red spot on their head, while inazuma kohaku have a continuous red streak from head to tail. Whatever their colors as ornamental fish, koi return to the natural golden-yellow color of common carp within a few generations if released into the wild.
The time in Japan when carp are at their most prominent is in the period leading up to Children’s Day on May 5. The carp has long been regarded as an auspicious sign of strength and perseverance, and many families with male children fly long tubular streamers called koinobori shaped like carp outside their homes at this time. As they ripple in the wind, the koinobori do in fact resemble vigorous, colorful carp, symbolically advancing up the great stream of life.
David Capel is a journalist living in Tokyo.
Note: This article first appeared in the June 2013 issue of the Japan Journal. Updated for TJJ ONLINE with additional photo, May 5 2021.