There are over 100 varieties of koi, which can be red, white, black, yellow, brown, gray, and green, and many combinations thereof. Koi resemble oversized goldfish and, in fact, koi and goldfish are both types of carp.

Koi are culturally significant and represent love and friendship in Japan. Some koi can live over 200 years, so they are passed down from generation to generation and considered a family heirloom in Japan. Varieties of koi are distinguished by their coloration and scale pattern. They are social, “schooling” fish.

These domesticated carp can live in aquariums, but their true value is in outdoor ponds and water gardens. They are mostly vegetarians—rice and corn are among koi’s favorite foods—but they will also eat live shrimp and even their own young, called “fry,” before the little fish’s coloration comes in. To ensure healthy, long-lived koi, it is best to give them standard koi food, which is at least 30 percent protein.

Koi are docile, social fish. Other fish species can be added to their pond if they are not aggressive.

These fish reproduce through spawning, usually in early summer, where a female lays a vast number of eggs and at least one male fertilizes them.