• Butterfly Koi possess some distinct features that set them apart from traditional stock.swimming koi image by Richard J Thompson from Fotolia.com
  
  The butterfly Koi is an ornamental species of fish related to wild carp and very similar to traditional Japanese Koi. The butterfly variety is regarded by some traditionalists as a negative influence on traditional Koi keeping, but many find it irresistibly beautiful. Like traditional Koi, butterflies come in several distinct and specific color morphs, though butterflies are bred largely for finnage rather than color.
  
  

Size and Shape

• Although there is some dispute in regard to the origins of butterfly Koi, many believe them to be crosses between long-finned carp and traditional Koi. Because of this, butterfly Koi share many of the physical features of carp; their bodies are long, slender and torpedo-shaped, with relatively large mouths. Where wild carp can grow to 3 feet in length, most butterfly Koi are somewhat smaller, around 2 feet on average. The main distinguishing feature of the butterfly Koi is the long, flowing fins. Butterfly Koi can have fins up to five times longer than traditional Koi.
  
  

Color

• Butterfly Koi share many of the same color patterns as traditional Koi. Koi colors are given in Japanese, where the art of raising these fish developed. Some common patterns include Kahaku, a pattern of bold red over a white body; Bekko, a stepping-stone pattern of black on a solid background; and Tancho, a simple crown of red on white. Traditional Koi are judged on the crispness and clarity of these patterns in addition to several other factors.
  
  

Differences From Traditional Koi

• In addition to the obvious difference of the butterfly's long, elaborate fins, these fish are generally much more slender in profile than their traditional cousins, where a wider, oval-shaped body is desired. Since traditional Koi are judged based partly on a ratio of fins to body, butterfly Koi have been disallowed at traditional Koi shows internationally. In addition, the emphasis of fins rather than purity of color has caused some strains of butterfly Koi to deviate from more traditional patterns or to display somewhat lackluster coloration.