The Difference in a Butterfly Koi From a Japanese Koi

Japanese koi and butterfly koi are ornamental, domesticated pond fish. Koi originated from carp that were selectively bred over generations to enhance their coloration. Japanese rice farmers kept the carp in ponds for food during the cold winters and noticed pleasing colors evolving. They isolated the most beautiful carp and bred them, leading to the varieties available today.

  1. Time Frame

    • The first Japanese koi were developed in the 19th century. The butterfly koi, however, is a much newer hybrid. It has been around only since the 1980s, when aquarists began experimenting with different koi hybrids. The butterfly koi is beloved by Americans, but is considered inferior by the Japanese and not bred there.

    Features

    • The butterfly koi and the Japanese koi share many characteristics. However, the butterfly koi has distinctive, elongated fins and a longer tail, giving it the appearance of steady flowing movement. The fins resemble the wings of a butterfly, which led to the name of the koi. The butterfly koi is considered hardier and is able to withstand colder temperatures better than the Japanese koi.

    Coloration

    • Both koi types come in a variety of colors. Butterfly koi come in white, yellow, orange, or all three. Because the hybrid is relatively new, many of them come only in a singular color. Japanese koi typically sport a variety of colors and patterns in red, white, yellow, black or orange.

    Habitat

    • All koi are considered pond fish. Japanese koi grow to 3 to 4 feet long. Butterfly koi grow to about 3 feet long. Both types may be kept in an aquarium when young, then moved to a pond with at least 50 gallons of water as they outgrow the tank. Both koi types have a lifespan of 25 to 35 years.

    Insight

    • Many Japanese koi breeders consider the butterfly koi inferior because it does not meet competitive standards set over the decades. As of 2010, butterfly koi are not allowed to compete in koi competitions in Japan. The butterfly koi, for example, does not meet Japanese criteria such as fin-to-body-ratio, an oval shape and specific patterns of coloration.