Koi, or Nishikigoi (Cyprinus carpio), are descendents of the common carp. This group includes the dull brown fish and the brightly colored varieties. What are known as koi in English are referred to more specifically as nishikigoi in Japan (literally meaning “brocaded carp”). In Japanese, koi is a homophone for another word that means “affection” or “love”; koi are therefore symbols of love and friendship in Japan.
The first koi started off as just a brown fish. In the 17th century Chinese rice farmers began keeping carp in their rice paddies and this practice found its way to Japan. The Japanese farmers notice some slight color variations in a few of the carp and began separating them to breed. Through selective breeding by the Japanese, numerous colors and patterns were developed. Koi varieties are distinguished by coloration, patterning, and scalation. Some of the major colors are white, black, red, yellow, blue, and cream. The most popular category of koi is the Gosanke, which is made up of the Kohaku, Taisho Sanshoku, and Showa Sanshoku varieties. In the early 20th century koi left Japan and were raised in Europe and eventually North America. Koi that have been well cared for have a life expectancy of around 50-70 years and have been known to live to be over 200 years old. It’s a common thing I’ve heard over the years that koi are just big goldfish and that’s not quite the case.
Goldfish were developed in China more than a thousand years ago by selectively breeding of Prussian carp for color mutations. By the Song dynasty (960–1279), yellow, orange, white, and red-and-white colorations had been developed. Goldfish (Carassius auratus) and Prussian carp (Carassius gibelio) are now considered different species. Goldfish were introduced to Japan in the 16th century and to Europe in the 17th century. Koi, though, were developed from common carp in Japan in the 17th century. Koi are domesticated common carp (Cyprinus carpio) that are selected or culled for color; they are not a different species, but a subspecies.
The length of an adult koi can reach from 2 to 3 feet and weight up to 35 lb.. On average they also grow about 2 centimeters per month. Because of their large size, they should only be kept in large ponds of at least 1000 gallons. On the other hand goldfish may only grow to be around a foot long. In general, goldfish tend to be smaller than koi, and have a greater variety of body shapes and fin and tail configurations. Koi varieties tend to have a common body shape, but have a greater variety of coloration and color patterns. They also have prominent barbels on the lip. Some goldfish varieties, such as the common goldfish, comet goldfish, and shubunkin, have body shapes and coloration that are similar to koi.
Do to the long life span of koi in Japan, koi are often passed down from generation to generation, as a family heirloom. With that said let me tell you about a very old fish named Hanako.
The Story of Hanako The Longest Living Koi Ever
Hanako (Japanese translation – flower girl) was the longest living fish ever recorded. A scarlet colored female that lived in Japan. Hanako passed away in July 7, 1977 at old age of 226. Born in 1751 in the middle of the Tokugawa Era, this made Hanako older than the United States of America!
Dr. Komei Koshihara, the last owner of koi Hanako in May 25,1966, made a broadcast to the whole Japanese nation through Nippon Hoso Kyokai radio station about the story of koi Hanako. Hanako was 215 years old weighing 7.5 kilograms and 70 centimeters long at the time of the broadcast. He explained that Hanako was passed down from his grandmother, who had inherited the koi from “olden times.”
Hanako’s age was verified by analyzing the rings on her scales the same way that the age of tree is aged, by counting the number of rings of growth on wood. The growth rings on the scale of Hanako were counted using a light microscope. The growth rings on a scale show a pattern of wide growth followed by a narrower growth. The differences in the width of the rings reflect the seasonal change of summer and winter. In the summer, fish eat more and grow more resulting in a wider growth ring. The narrower growth represents the slower metabolism during the cold weather. In order to analyze the exact age of Hanako, she was removed from the pond in the mountains of Mino Province. Two scales from different parts of her body were taken off. The individual annual rings on the scale were analyzed over two months in Laboratory at Nagoya Women’s College. Professor Masayoshi Hiro and Both Dr. Koshihara were happily surprised when Hanako was proved to be 215 years old at the time. After this discovery, the remaining five koi in the same pond were examined as well. After a yearlong study, the results showed that they were all over 100 years old as well.
No one knows the exact reason for her long lifespan, it’s thought that the crystal clear waters of the Japanese mountains and the love and care of her owners was the key. Koi are generally live a long life with a span of approximately 50 years. There are many carp that live over a century. This is one of the reasons that koi have gained such admiration in Japan and the rest of the world. Hanako’s story is a great example of the long lives that koi live, as koi are one of the longest living vertebrae on Earth.