Butterfly Koi, Longfin Koi, or Dragon Carp are a type of ornamental fish notable for their elongated finnage. The fish are a breed of the common carp, Cyprinus carpio, (which includes numerous wild carp races as well as domesticated koi ("Nishikigoi"). A giant grouper at the Georgia Aquarium Fish are aquatic vertebrates that are typically cold-blooded; covered with scales, and equipped with two sets of paired fins and several unpaired fins. ... A breed is a domesticated subspecies or infrasubspecies of an animal. ... Binomial name Cyprinus carpio (Linnaeus, 1758) The Common carp or European carp (Cyprinus carpio) is a widespread freshwater fish distantly related to the common goldfish, with which it is capable of interbreeding. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... Binomial name Cyprinus carpio (Linnaeus, 1758) Koi (鯉（こい）, Rōmaji: koi, pronounced IPA: ) are ornamental domesticated varieties of the common carp Cyprinus carpio, originated from China and widely spread in Japan. ...

Butterfly Koi originated in the mid 20th century as a result of an effort to increase the hardiness of traditional koi. Japanese breeders interbred wild Indonesian Longfin river carp with traditional koi. The resulting fish had longer fins, long barbells, pompom nostrils, and were hardier than koi. These were known in Japan as “onagaoi” or "hire naga koi", or translated in English “long tail koi”. Randy LeFever, the son of Wyatt LeFever, a noted breeder of koi, is credited with suggesting they looked like butterflies, a trait for which the breed is named. They are also sometimes referred to as Dragon Koi.

Nishikigoi Judging

a butterfly koi, viewed from above

Butterfly koi cannot be judged using the traditional criteria of used for koi judging. The standard criteria used in these events have evolved over many years, and they are specifically tailored to rate the characteristics of koi. According to an article in KOI USA magazine, the following characteristics are largely the basis for the unsuitability of butterfly koi in traditional competition: Image File history File links Download high-resolution version (800x663, 46 KB) Longfin. ... Image File history File links Download high-resolution version (800x663, 46 KB) Longfin. ...

Conformation - The ideal shape of a koi has been set by tradition to be generously oval. By contrast, butterfly koi are naturally more slender. This difference is amplified by the fact that traditional koi judging is done from a top-down viewing angle.

The Relationship Of Fin To Body – The ratio of fin-to-body is an important scoring criteria in nishikigoi competitions. By design, Longfin embody a ratio that exceeds the standards applied to nishikigoi by 500 to 1000 percent.

Pattern Differences - Great energy has been given to developing butterfly koi versions of traditional koi patterns, (eg: kohaku, sanke, show, utsuri and ogon). Butterfly koi, however, exhibit these patterns in a slightly different way.

For these reasons, Japan’s airinkai (the organization that sanctions all Japanese nishikigoi competitions) have disallowed butterfly koi from competitive judging for many years, although their American counterpart the American Koi Club Association (AKCA) has (as of June, 2006) reportedly created new standards for judging butterfly koi at future AKCA competitions.

Popularity as an ornamental fish

In the United States, butterfly koi are sold in large numbers for use as ornamental fish. Despite this, many people hate Kois due to the aggresiveness they display

Unpopularity amongst koi breeders

Butterfly koi are strongly disliked by many keepers of traditional koi who view the breed as inferior to koi. This polarization of traditional keepers may be the reason why some koi retailers do not sell butterfly koi, and why many of Japan’s famous and most prestigious breeders do not breed butterfly koi today.