Koi, or more specifically Nishikigoi, are Amur carp or grass carp with colored varieties preserved in outdoor ponds or water gardens for decorative purposes. We cultivate the colors of koi for ornamental purposes. Ornamental koi come in a wide range of colors and patterns due to breeding in Niigata, Japan, in the early 1800s. The Japanese differentiate between several varieties based on coloration, patterning, and scalation. White, black, red, orange, yellow, blue, and cream are some of the most common colors. The Gosanke is the most popular koi that includes a slew of breeds like the Kohaku, Taisho Sanshoku, and Showa Sanshoku varieties.
Carp are a large family of fish that originated in Central Europe and Asia. In East Asia, people domesticated many carp species for ornament and food. Carp are coldwater fish, and their ability to adapt to a wide range of climates and water conditions has allowed the domesticated species to spread to new places, including Japan. Natural color mutations would have occurred in all populations of these carp. Chinese introduced carp breeding to achieve color mutations. When they bred a Prussian carp, they get to grow a goldfish.
Koi (Nishikigoi) from a Museum in Ojiya city, Niigata prefecture, Japan. (wikimedia)
The Amur carp is a species of cyprinid that is endemic to East Asia. People thought it is a subspecies of the common carp, but it is now considered a separate species. People bred Amur carp to cultivate as a food in China since at least the fifth century. In Japan, we can found colored carp in the accounts in Nihon Shoki (Chronicles of Japan), a Japanese history book published in 720. Emperor Keiko praised colored carp in a pond in the Mino area in 94, and Emperor Suiko saw them in the garden of Soga noUmako's residence in 620, according to the Nihon Shoki. In Japan, The systematic breeding of ornamental koi started in the 1820s in Ojiya and Yamakoshi, Niigata Prefecture (located on Honshu's northeastern coast). Red carp were the first to be bred, followed by pale blue Asagi and white, red, and yellow Bekko.
In 1830, people produced the Sarasa variety with a red on white pattern. They create a Ki Uturi variety, which is a yellow variant of koi. People bred all types of Nishikigoi varieties except for the Ogon variety, a single-colored, metallic koi. The hobby of keeping koi became famous across the world. Many pet aquarium stores sell them, with higher-quality fish available from specialist dealers. Koi collecting has evolved into a social activity. Hobbyists form clubs, share their expertise, and assist one another with their koi. In recent years, some Chinese imported large quantities of koi from Niigata, Japan, driving up the price of high-quality carp. A Chinese buyer paid $2 million for one carp in 2018, the highest price ever paid. Purchased carp are also bred in China and sold to other countries, and many breeds are spreading around the world.
Variety of Koi in a Pond. (wikimedia)
There are more than 100 varieties of koi produced through breeding, according to Zen Nippon Airinkai, a group that leads the breeding and dissemination of koi in Japan. People divided each class into groups. Coloration, patterning, and scalation differentiate koi varieties. White, black, red, yellow, blue, and cream are some of the most common colors. Although the number of possible colors is nearly infinite, breeders have recognized and named several distinct categories. Gosanke, which includes the Khaku, Taish Sanshoku, and Shwa Sanshoku varieties, is the most well-known.
The development of new koi varieties is still ongoing. Ghost koi, a hybrid of wild carp and Ogon koi created in the 1980s, have become extremely popular in the United Kingdom. We can differentiate it from its metallic scales and are a hybrid of wild carp and Ogon koi. Butterfly koi or dragon carp have long and flowing fins, a cross between koi and Asian carp. Some people believe that butterfly koi and ghost koi are not real Nishikigoi.
A koi head close up. (wikimedia)
Koi's bright colors make them vulnerable to predators; a white-skinned Kohaku against the dark green pond is a visual dinner bell. Herons, kingfishers, otters, raccoons, mink, cats, foxes, badgers, and hedgehogs can all deplete a pond's fish population. A well-designed outdoor pond will have areas too deep for herons to stand, overhangs high enough above the water to keep mammals out, and shade trees overhead to keep aerial passers-by at bay. Stringing nets or cables above the surface may be necessary. We install pumps to keep the water clear in our koi ponds.
Koi is a fish that eats everything. Peas, salad, and watermelon are among the meals they consume. Koi's food should be nutritionally balanced and intended to keep afloat, encouraging them to come to the surface. Koi can be tested for parasites and ulcers while they are eating. Koi are bottom feeders by nature, and their mouths have evolved to accommodate this. Because some koi prefer to eat from the bottom, food manufacturers create a mix of sinking and floating food.
Feeding some koi. (wikimedia)
Koi understand the people who feed them and congregate around them when it's time to eat. We can teach the koi to eat from our hands. Their digestive systems slow to a halt in the winter and they eat very little, maybe just a few nibbles of algae from the bottom. When the water temperature falls below 10 degrees Celsius (50 degrees Fahrenheit), feeding is not recommended. Hobbyists should ensure that proper oxygenation, pH stabilization, and off-gassing occur in small ponds over the winter so that they do not die. Their appetites return only when the water warms up in the spring.
The Ojiya no Sato Museum in Niigata Prefecture, Japan. (wikimedia)
We know that some koi can live up to 100 to 200 years old. Several people owned a famous scarlet koi named Hanako, which the last known owner is Komei Koshihara. Hanako was at least 226 years old in July 1977, The koi is a tough fish, and koi maintain their toughness. Koi are coldwater fish that do best when kept at temperatures between 15 and 25 degrees Celsius (59 and 77 degrees Fahrenheit). They do not tolerate long, cold winters, and their immune systems are not adept a temperatures below 10 degrees Celsius. In the tropical area where the summers are hot, koi ponds typically have more depth, while in areas where the winters are harsher, ponds usually have a minimum depth of 1.5 m (5 ft). Koi keepers and breeders must design a koi pond appropriate to their koi species when they want to raise show-quality koi that have developed degrees Celsius.
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