butterfly koi

Butterfly Koi



This is a brown and grey fish with long fins. It originated from Indonesia where it was found in canals and ditches. Initially, most people found this particular type of fish ugly considering its looks, but that has since changed over time after long periods of breeding. They have characteristic long fins. They could also be bred back into color as well as many colorful lines similar to the orginal long fin koi.

One of their most selling point is the fact that they are robust and are also very resistant to almost all diseases. The name ‘butterfly’ was due to their looks as they resemble a butterfly.

Butterfly koi Size

Butterfly koi displays a great growing pattern. The signature fins keep growing as the butterfly koi grows, making it look more and more impressive in the process. At some point however, the blood vessels can no longer sustain the fins growth and that is where they stop. When fully grown, butterfly koi resembles a long, slinky dragon swimming in your aquarium fish tank. They can grow up to 36-40 inches, depending on the food amounts. They however can not compare to the regular koi in size.

Types of Butterfly Koi

  1. Sorogoi fish

This type of butterly koi when fully grown as adults are incredible. It has a characteristic grey or black fish net pattern over its body. They grow huge as they are robust and they are mysterious.

  1. Black butterfly koi

Another type of butterfly koi is black butterflies, which are considered by some people as being better and even coolest. They are not easily found and hence the effect is rare making it special to say the least when it happens. They can have scales but sometimes they don’t. Among this type, the rarest and most valuable is the doitsu, karasu butterfly. This fish is black, has no scales, and has long fins.

They grow up and become very large because their genes are not as strained as some of the brighter colored fish. And if they have no scales, the body is a glistening jet-black. The fins keep growing until the entire fish is broad, and streams long black robes behind it. They look like a jet-black dragon.

Butterfly Koi Fins

In a striking resemblance to any other koi, the fins of the butterfly koi are made up of dozens of rays of cartilage that radiate outward and support the fin. These rays generally grow very straight, but past the point of normal length they can grow wavy. The fish that grow straight rays even into the lengthier parts of the tail are more impressive looking and would be more valuable.

Caution when handling butterfly koi

One problem with butterfly koi is that they are often handled the same way as regular koi. Broken fins and tails are common when they are fully grown. This means that it’s ┬ánormal to see bends and waves in the fins and tail of butterfly koi partly because of growing that way, but also because of netting-damage as a juvenile. As an adult, a split tail or fin often does not heal well and remains split. All of the above is irrelevant to the casual observer, the impact of the fish is exactly the same, but you might notice variations in fin quality and you may care enough to choose one fish over the other based on that.


As to whether it is a true koi or not, the butterfly koi is a true koi. The butterfly koi is very unique and satisfying to look at and you will be fascinated by there characteristic long fins and the beautiful colors. It is a great addition to your fish tank.

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