Take a dip into the fascinating world of koi fish, or as the Japanese call them, nishikigoi. These colorful carp are no ordinary fish, they're an artistic expression that brightens up backyard koi ponds and water gardens. The array of koi varieties that we know today originated from breeding in Niigata, Japan, in the early 19th century. They come in a rainbow of colors, including white, black, red, orange, yellow, blue, brown, and cream, with some having metallic shades of gold and silver-white scales. The most beloved type of koi is the Gosanke, a group made up of three varieties: Kōhaku, Sanke, and Shōwa.

Carp, a group of fish originating from Central Europe and Asia, were domesticated in China as a food source due to their ability to survive and adapt to various climates and water conditions. This allowed them to be grown in new locations, including Japan. The systematic breeding of ornamental koi began in the 1820s in an area known as "Nijūmuragō" Japan. Red and white koi fish were introduced in the Nijūmuragō region through crossbreeding, complementing the traditional black koi and resulting in a new breeds.

Around 1875, the popularity of colored koi grew rapidly, leading to an increase in the number of breeders and the production of expensive koi. However, the Niigata Prefecture banned the breeding of ornamental koi, citing speculation as the reason. This decision had a significant impact on the industry. Fortunately, the ban was lifted shortly after due to the breeders' petition. Back then, the colors of koi were limited to Kōhaku, Asagi, Ki Utsuri, and a handful of others. All other Nishikigoi varieties were developed from these original strains, except for the Ogon variety, which was created more recently.

Koi breeding in Nijūmuragō prospered for a couple reasons. Farmers would cultivate koi in unused fields for winter food. Second, the presence of secret mountain rice fields unknown to the lords, enabled farmers to evade taxes and accumulate wealth. Over time, koi breeding evolved into a farmer's hobby, with high-quality koi being bought and sold. The name Nishikigoi didn’t come until around 1910.

The Tokyo Taisho Exposition of 1914 was a significant event for koi breeders. During the exposition, koi were showcased for the first time. They managed to capture the attention of the public and even won a silver medal. After the event, eight koi were presented to the Crown Prince (Emperor Showa), sparking a surge in sales and a rise in the market value of koi.

Koi keeping has since become a widespread hobby, with enthusiasts finding them in pet stores and specialist dealers alike. It's taken on a social aspect, with passionate hobbyists joining clubs, exchanging their expertise, and assisting each other with their koi collections. In recent years, wealthy Chinese individuals have been importing vast quantities of koi from Japan's Niigata region, leading to a surge in the price of high-quality koi. In 2018, a Chinese collector purchased one koi for around $1.8 million, setting a new record for the most expensive koi ever purchased.

Today, there are over 100 sought after koi color patterns with more to come.