Butterfly Koi: Origins, Care, size, types, & More!

A butterfly koi swimming gracefully through a pond is a beautiful sight. With its long-flowing fins, it’s no wonder that this relatively new variety of koi has seen a surge in popularity.

What are butterfly koi?

In the simplest terms, butterfly koi is a long-finned variety of the ever-popular koi fish. Butterfly koi is the popular name for what is also known as the long-fin koi or dragon carp

They are a new variety of koi and are still not widely accepted among koi purists. They aren’t even considered real koi in some circles but rather as “mutts”. Fortunately, their ever-increasing popularity is hard to ignore and this attitude is gradually changing. 

Butterfly Koi Vs Regular Koi

Photo showing a regular koi vs a butterfly koi next to each other

There are a few key differences between butterfly koi and regular koi. The most apparent of these, is, of course, the long fins. These long fins will continue to grow throughout their lifetime, unlike traditional koi. With traditional koi, the fins will grow to a natural length relative to the proportion of their body size. The fins of a butterfly koi will exceed the breed standards for regular koi by as much as 1000%. 

In addition to their famous long fins, these koi will also have slightly longer whiskers than their traditional cousins. 

The body shape of butterfly koi is also a bit different from regular koi. Standard koi have a generally oval shape. In contrast, the butterfly koi are a naturally more slender torpedo shape. This shape is broad at the shoulders and tapers towards the tail.

According to strict Japanese koi judging criteria, butterfly koi or dragon carp are not even real koi. Due to the proportions of their fins to their body size and some other factors, they do not fit the rigid traditional koi mold.

Fortunately, this attitude is changing and the Associated Koi Clubs of America (AKCA) has adopted judging standards for the long-finned koi. 

History & Origin

There is some debate as to who or where butterfly koi were originally bred and developed. While they were likely first being developed in Japan by Suda Fish Farms, they were also being developed in the U.S. by Blue Ridge Fish Hatchery close to the same time. 

Both of these breeders began their work on long-finned wild carp found in the ditches and canals of Indonesia in the early 1980s. They appeared gangly and were colored plainly in browns and greys. These wild carp were ugly and there was little initial interest in them.

Blue Ridge and Suda Fish Farms crossed these ugly long-finned carp with their domesticated ornamental koi. Through much work, they were able to keep the long graceful fins but breed in the beautiful colors of ornamental koi.

Regardless of who was the first to breed these long-finned koi, they climbed to popularity through the collective efforts of both breeders. 

Those Long Fins

Long finned golden butterfly koi carp in pond

Most fish species have fins that grow to a specific length. This growth is controlled by a fish’s genes. Some fish however have a genetic mutation that signals the fins to simply keep growing. This is the case with our lovely butterfly koi. In addition, other fish such as betta fish, long-fin black tetras, and long-fin oscars have this same mutation. 

The older the fish, the longer these fins grow. As these fins grow the value of the fish increases tremendously. 

This long-fin gene is dominant so breeding it into the colorful traditional koi isn’t a problem. The long fins are retained and the vibrant colors of the ornamental koi are transferred over. 

Types of Butterfly Koi

You will find many of the same color varieties in butterfly koi as you do with traditional koi. Some of the most sought after varieties of long-finned koi include:

  • Asagi
  • Goshiki
  • Kumonryu
  • Kohaku
  • Utsurimono
  • Sanke
  • Saragoi
  • Showa
  • Shusui

Keeping Butterfly Koi / Butterfly Koi Care

Do you already have some experience with keeping koi? If yes, the good news is that their care isn’t really any different than regular koi. Make sure they have enough space to live, clean water, plenty of aeration, shelter from predators, and are well fed. These needs are easily met with proper planning and care. 

Butterfly koi can be kept with regular koi and any other companion animals that are normally kept with koi. In some cases, they can even be kept with turtles if care is taken. 

The only true difference in care between the two is handling. Due to its long delicate fins, damage often occurs when netting or handling. This can cause waves and bends in the fins as they do not always heal well. Because of this, delicate care should be taken when handling these fish or it should be avoided altogether if possible. 

How Long Does a Butterfly Koi Live?

Butterfly koi will live as long as traditional koi. Under ideal conditions, this can be up to 30 years on average. It is reported that the oldest living traditional koi was 226 years old. While this may or may not be true the same cannot yet be said about butterfly koi. 

They are theoretically hardier due to the fact that they are hybridized with wild carp. But since they were recently developed in the 80’s they have not yet had the chance to show their true longevity. 

How Big Do Butterfly Koi Get?

Butterfly koi have thinner bodies than regular koi which gain more girth. Aside from this, butterfly koi can grow just as long as a regular koi. This means that they can easily reach lengths of 2 feet and even into the 3 plus foot range!

As with traditional koi, this can take anywhere from 2-4 years to reach these sizes under ideal conditions. 

Final Thoughts

While some may say butterfly koi are not true koi, it’s hard to ignore their popularity. This popularity will continue to grow and they will inevitably find their way into more ponds.