Botanical name: Cyprinus rubrofuscus var. "koi"
Common name: Koi
Family name: Cyprinidae (Carp family)
Native range: Domesticated origin
Location in Duke Gardens: Historic Gardens
By Katherine Hale
Marketing & Communications Assistant
Visitors to the Historic Gardens often marvel at the colorful koi in the pond at the base of the Terrace Gardens, complemented by the ornamental water lily display in the warmer months. Unlike surrounding plantings that change with the season, however, these fish are permanent residents, delighting onlookers year-round with both their beauty and their habit of periodically rising to the surface with mouths agape.
“Koi” is the Japanese word for carp—in this case, the Amur carp (Cyprinus rubrofuscus), which is native to rivers and lakes across east Asia. Nineteenth-century Japanese farmers raised wild carp in ponds and streams to supplement their diets, which resulted in unique strains with striking patterns on their scales. By the early 20th century, what began as household aquaculture had transformed into an extensive hobby, one that gained nationwide attention at a 1914 exposition in Tokyo.
Since then, more than 100 varieties of nishikigoi, or “brocaded carp,” have been developed, with prize specimens selling for thousands of dollars to collectors. Popular varieties include the Kōhaku, which is pure white with red markings; the Showa, which is black with red and white markings; and the Bekko, which is white, red or yellow with dark ink-like splotches. Another notable form is the “butterfly” or “dragon” koi with long flowing fins, which is a hybrid between established koi lineages and their wild counterparts.
Like other species of carp, koi are omnivorous bottom feeders, with distinctive barbels, or whisker-like appendages on their lips that aid them in finding food in low-light or high-sediment conditions. (The barbels are also an easy way to distinguish koi from goldfish, as the two can be easily mistaken for each other when small.) As temperatures drop in the winter, the fishes’ metabolism slows down and they require very little food until the water temperatures rise again. Regardless of the time of year, however, visitors to Duke Gardens are asked to refrain from feeding the koi, as they have a special nutritionally balanced diet to keep them healthy.
Unfortunately, the same bright colors that make them stand out to human eyes also make koi more vulnerable to predators—especially the Gardens’ resident great blue heron (Ardea herodias). While smaller koi ponds are often netted to keep the fish safe, this one is mostly too deep for the heron to wade in—thus protecting the fish as long as they keep away from the edge.
Photos from top: Koi approach the surface of the koi pond in the Historic Gardens, by Clarence Burke; close-up of a silver koi showing the barbels under its mouth, by Cathi Bodine; a black and white "butterfly" or "dragon"-type koi with longer fins than are typical, by Brian Wells.