• Koi are the ornamental varieties of the domesticated common card (Cyprinus carpio).

• Koi keeping is believed to have originated in Niigata, Japan, where carp were kept as a reserve food source by farmers. Some of them noticed the brilliant colors of the carp and began to selectively breed them to bring out their color.

• Koi varieties are distinguished by coloration, patterning, and scalation. Popular colors include black, blue, cream, red, white, and yellow.

•They are also known as ‘nishikigoi’ in Japanese, which means ‘brocaded carp’.

• The koi’s preferred habitat is cold water.

• Koi are omnivorous and will eat a wide variety of food.

• The three most popular varieties of koi in Japan are the Kohaku, Showa, and Sanke.

• Some koi are said to have achieved ages of 100-200 years; a scarlet koi named Hanako was proven to be 225 years old and to have outlived several owners.

• The most popular category of koi is the Gosanke, which is made up of the Kohaku, Taisho Sanshoku, and Showa Sanshoku varieties.

• In Japanese, the word ‘koi’ sounds like the word for ‘affection’ or ‘love’. No wonder koi are symbols of love and friendship in that country.

• In China, a legend that is thousands of years old tells of how koi transformed into dragons by swimming up a waterfall and through the Dragon Gate using their perseverance and endurance―which is why koi still symbolize those qualities to this day.

• Koi are the official symbol for the Children’s Day festival, held every May 5, in Japan. Families hang koino bori or koi windsocks outside for every household member.

• Like carp, koi are hardy fish, preferring temperature ranges of 15–25 °C (59–77 °F), but long, cold, winter temperatures can compromise their immune systems.

This story appeared in Animal Scene’s April 2015 issue.