About Koi

Koi is the common name for Nishikigoi. These are spectacular domestic fish bred in Japan for hundreds of years that now can be found in many places throughout the world with a large, devoted following. A particularly beautiful koi can be worth thousands of American dollars. The largest price ever paid for a koi was $850,000. Koi do not make good fish to keep in aquariums--unless they are extremely large aquariums. Mostly they do best in natural or man-made ponds.

  1. History

    • It is unknown whether koi originated in China or Japan. Both countries took the common carp--thought to be a living symbol of good luck and wealth--and did selective breeding to make specific colors and fin shapes. A book about keeping carp was written in China about 500 BCE. It was in Japan that breeding koi became a passion. "Koi" is a Japanese word. It's thought that the first fish recognizable as a koi was bred in the late 1700s or early 1800s. Koi were first exported from Japan about 1915. Koi became very popular very quickly in Europe, America and all over Asia.

    Identification

    • Koi are long, sleek, almost torpedo-shaped fish that resemble common goldfish. However, they often have whiskers like their carp ancestors. They have spectacular colors in a variety of patterns. These colors and how sharply defined the patterns are determines the cost of the fish. Solid colors can be in goldfish gold, coppery gold, silver, white and black. Many patterns include any color with white, a solid body and a different colored cap on the head or even a fish with three or more colors.

    Size

    • Koi are big fish. On average, they grow to three feet long, but they have been known to grow to five feet long. This is why they need to be in a pond with a good filter and aeration system, as living in an aquarium can often kill them. You can never keep the water chemistry right in such a small environment.

    Warning

    • Koi are omnivorous fish. Although they love plants, they also love eating smaller fish. If you decide to keep any other fish in your koi pond, they need to be nearly as large as your koi. Catfish, plecostomus and very large goldfish have been known to live quietly with koi.

    Expert Insight

    • Koi are very intelligent fish and can recognize people. They will very easily learn to take food from your fingers. They can snap when they are spawning and should be left alone then.