Butterfly Koi Fish: Ultimate Care Guide


Butterfly Koi (Cynprinus carpio) is a long fin koi that originated in Indonesia, and are a cross between a long-finned carp and traditional Japanese Koi. According to strict Japanese definitions, Butterfly Koi are actually not considered members of the Koi family by many fish connoisseurs and aquarists. Butterfly Koi are bred widely and have become a very popular choice of fish for those that have outdoor ponds, as well as large indoor aquariums.

Because the Butterfly Koi is bred by crossing two types of fish, there are many variations that fall in their category. A few of these types of Butterfly Koi include Asagi, Goshiki, Kumonryu, Kohaku, Hariwake, Soragoi, and Ki Utsuri. All of these types have similar origin but vary in their color patterns.

For example, the Kohaku Butterfly Koi has a solid white base with colors of red and orange overlapping on top of the white, whereas the Asagi Butterfly Koi has a blue net-like pattern on its body that is surrounded by orange coloration. The Goshiki Butterfly Koi has a solid white base with black and blue edging, as well as a red overlay. In comparison, the Kumonryu Butterfly Koi has pattern combinations of black, white, and grey all over its body. The Hariwake Butterfly Koi has a metallic, white body with orange and yellow colorations to contrast, while the Soragoi Butterfly Koi is entirely grey or silver in color with a net-like pattern. There is also the Ki Utsuri Butterfly Koi, which is the rarest of all the types and has a yellow and black body pattern that helps it stand out from the others in its category.

Butterfly Koi
Butterfly Koi

Butterfly Koi Care

Taking quality care of a Butterfly Koi is essential to ensuring they live a long and happy life. Although Butterfly Koi care is considered generally easily, it is still important that their habitat is well maintained and kept to their standard. Frequent tests should be conducted on the Butterfly Koi water quality, to ensure conditions are suitable. Butterfly Koi can live in a variety of environments, so paying close attention to their demeanor and what they prefer can help to ensure they are at their full happiness potential, in a pond or a tank.

Butterfly Koi Temperature

The Butterfly Koi needs a water temperature in their tank that is consistent with their outdoor habitat. Because they are cold-water fish, they can withstand water temperatures that range from 33 to 90 degrees Fahrenheit, although their water temperature should be maintained between 65 and 75 degrees Fahrenheit. It is crucial to the wellbeing of the Butterfly Koi that their water temperature is kept at bay in extreme conditions. A pond de-icer can be extremely useful for the Butterfly Koi habitat if temperatures drop below 33 degrees Fahrenheit, and a pond deeper than three feet also gives them an opportunity to go dormant safely in the cold. In contrast, water that is too warm in temperature can cause diseases with less dissolved oxygen and more toxic ammonia.

Dissolved oxygen tests should be run periodically and are especially crucial in warmer weather conditions. When water temperatures are too high, oxygen levels might be too low for the Butterfly Koi. A good indictor that oxygen levels are depleting is if the Butterfly Koi is coming to the surface of the pond to gasp for air. The Butterfly Koi pond should have adequate aeration through air pump or waterfalls, with an oxygen level reading of 6.00 ppm or above.

Butterfly Koi Water pH

Butterfly Koi prefer pond water with a pH that ranges from 7.5 to 7.8, with slight alkalinity. Readings of the pond pH should be done in the morning and evenings because conditions can fluctuate during the day and night. 

Butterfly Koi are extremely sensitive to ammonia in their water and there should be zero traces of it in their habitat. Water testing will help to identify is there is any ammonia present in a Butterfly Koi pond, so that it can be controlled immediately. Water should be changed on a consistent basis to ensure that no ammonia develops in the environment.

Butterfly Koi Size

The average size of a Butterfly Koi is 12 to 15 inches in length at full maturity. Although this is the general length for this species, some Butterfly Koi are recorded to reach a size of up to three feet in length when they are taken care of in the most favorable of conditions. The Butterfly Koi not only grows in size with age, but also in grace and beauty as they develop long flowing fins and whiskers.

Butterfly Koi Food & Diet

A Butterfly Koi diet is easy to maintain, with high-quality pellet food making up majority of their diet. These pellets will ensure that the Butterfly Koi maintains a balanced diet and intakes enough nutrients to keep them healthy and growing. Butterfly Koi also enjoy live treats and can eat everything a human would, including oranges, lettuce, peas, and watermelon, as well as shrimp and algae.

During warm weather days, a Butterfly Koi should be fed once to twice a day. In cold weather, Butterfly Koi should be fed less because of low physical activity levels and the inclination to go into hibernation. It is also advised to not feed Butterfly Koi after rainstorms because they need oxygen to digest their food and after extreme weather, oxygen levels in the water drop.

Butterfly Koi Lifespan

A healthy Butterfly Koi will live an average of 25 to 30 years in captivity when properly cared for. This means that they have correct water parameters, high water quality, and a suitable diet. Because of their hardiness and resistance to disease, Butterfly Koi are known to live robust lives if they are taken care of well.

Butterfly Koi Tank Setup

A Butterfly Koi fish can be kept in a tank, as long as there is enough space for this very active fish to swim around freely. The tank substrate should be a muddy substance, because Butterfly Koi like to search and dig through sediment when they are looking for food. Butterfly Koi also enjoy aquatic plants and foliage, so a few of these can be included in their tank to keep them satisfied with an interactive environment.

Butterfly Koi Tank Size

One Butterfly Koi needs at least 250 gallons of water in their tank, because they are large and energetic fish. If more than one Butterfly Koi is going to be kept in the same tank, at least 1000 gallons is more suitable for the tank size. The tank should also have deep and shallow water because Butterfly Koi like to fluctuate between each water level in their environment depending on temperature and the time of day.

Butterfly Koi Pond Setup

A Butterfly Koi pond should be set up to ensure quality water conditions and proper aeration. A well-aerated pond with plenty of aquatic plants and foliage will make a Butterfly Koi very happy in its new home. While this fish enjoys plants, too many should be avoided because they can interfere with the oxygen levels that are appropriate for the Butterfly Koi.

Butterfly Koi Pond Size

Because Butterfly Koi grow to such large size, a pond that holds at least 1000 gallons is recommended for the overall well-being of a group. These fish are also very graceful swimmers, and they need adequate room to roam freely around their habitat.

Butterfly Koi Breeding

The Butterfly Koi breeding process is pretty straightforward, but also involves some interference when picking the most fit Koi to mate, as well as removing the eggs from the community environment for individualized care. Butterfly Koi mating season begins in the late spring, where water temperatures reach 68 degrees Fahrenheit. Male Butterfly Koi will start to exhibit mating tubercles when they are ready to breed, which appear as white spots on the head and pectoral fins.

How Were Butterfly Koi Developed?

The Butterfly Koi originated when a population of brown and grey carp were found in the 1980s in a series of canals and ditches in Indonesia. A company in New York tried to bring the fish to the United States to sell, but people were not buying them since they were “ugly” in nature. That is until a group of breeders at Blue Ridge Fish Hatchery decided to purchase these fish to observe them and eventually bred them over the next several years with their finest regular-fin Koi. They then discovered that this breeding resulted in colorful Koi fish that still maintained their long-fin nature that makes them so unique.

How to Breed Butterfly Koi?

Once Butterfly Fish males are displaying signs that they are ready to mate, the two most desirable Butterfly Koi should be chosen based on their eye and color brightness. The male and female Butterfly Koi can then be left alone together to breed. Several days after the mating ritual begins, the female Butterfly Koi will lay eggs that the male will immediately fertilize them.

Once fertilized, the eggs should be removed with a spawning mop and placed in a sperate pond, otherwise the Koi will eat the eggs. Three to seven days after incubation, the eggs with hatch and baby Butterfly Koi will attach themselves to the habitat walls for another several days. Once the baby Koi are ready to begin eating, they will swim to the top of the water and can be fed chunks of fresh brine shrimp or finely ground Koi protein food. Once the baby Koi reached ½ an inch in length, they can be fed small, pellet food and work their way up to the same food as the parent Butterfly Koi, where they can then be returned back to the community habitat.

Butterfly Koi Male or Female

Butterfly Koi females tend to be larger than their male counterparts, with more circular bodies that help to differentiate the two apart. The male Butterfly Koi also have more pointed and solid pectoral fins than females, whose appears more round in shape. The males also have longer and thicker pectoral fins, whereas females have shorter and thinner ones.

Butterfly Koi Disease

Butterfly Koi are prone to a few diseases and should be monitored to ensure that no symptoms occur. Some of the symptoms that are associated with disease among Butterfly Koi can include but are not limited to loss of appetite, clamped fins, open wounds, ulcers, white spots, self-isolation, restlessness, and gasping at the pond surface. Any of these signs of behavior could point to illness for a Butterfly Koi and should be attended to as soon as possible.

Butterfly Koi can suffer from bacterial infections, which should be treated by isolating the infected Butterfly Koi in their own tank space. A vet should be consulted for further treatment and a prescription of medication for the fish may be recommended.

Parasites can also pose a health concern to Butterfly Koi and should be removed as soon as they are identified. These unwanted parasites can be removed from the Butterfly Koi with tweezers, but it is important that the entire body is removed from the fish to avoid further infection. If infection occurs, a vet can be consulted for further steps.

Butterfly Koi can be easily infected with a disease called Koi herpesvirus or KHV. This is a very contagious virus and there is a very high chance that once a fish is infected, it will likely die in the following days. The fish that survive can carry the virus and infect other fish, as well as potentially the entire tank. Symptoms of KHV include shortness of breath and red or white spots on the gills. Infected fish should be isolated and moved to their own tank as soon as possible.

Butterfly Koi Tank Mates

Choosing appropriate tankmates for the Butterfly Koi can be a nuisance because they are a cold-water fish. Finding other tankmates that share their habitat needs and lifestyle can be difficult, but still accomplished if a community space is desired.

Are Butterfly Koi aggressive?

Butterfly Koi are considered extremely social, calm, and amiable in their environment. Their activity level varies from fish to fish, where some are playful, and others prefer to stay aloof. Although the Butterfly Koi is often very friendly, they can occasionally turn aggressive with other species of fish in their habitat. For this reason, a Butterfly Koi should be confirmed as non-aggressive before introducing other species to its space. These fish should also not be placed in the same habitat with fish who are anti-social, as it might cause problems.

Compatible Tank Mates for Butterfly Koi

Butterfly Koi can be kept in a tank with other non-aggressive fish species that share their same needs in relation to water parameters and lifestyle. A few examples of tank mates that are compatible with Butterfly Koi are Pond Goldfish, Barbs, Catfish, Golden Orfe, Tench, and Pleco if the fish are being kept in a controlled tank.

Incompatible Tank Mates for Butterfly Koi

Butterfly Koi should not be kept in a tank with overly aggressive fish, fish that are too small, species that move at a slow pace, and fish that do not do well in outdoor habitats. A few examples of tank mates that are incompatible with Butterfly Koi include Cichlids, Guppies, Danios, and Fancy Goldfish.

Where can I Find Butterfly Koi for Sale?

Butterfly Koi are a popular species of fish and are therefore readily available from most online stores, and Koi breeders. Because many stores sell low-quality Butterfly Koi, it is important to conduct thorough research and only buy from a reputable retailer. If possible, the Butterfly Koi should be inspected before purchase to ensure that it is healthy and of good standing before making the investment.

Butterfly Koi Price

Because of their beauty and popularity, Butterfly Koi fall on the higher end of the price spectrum for aquarists. The average price for a Butterfly Koi is between 80 and 200 dollars, depending on their appearance and the source of purchase. With a high price point, the Butterfly Koi should be considered an investment that will add value and elegance to any environment they are introduced to.

Are Butterfly Koi More Expensive Than Standard Koi?

Butterfly Koi can be more expensive than standard Koi if they have a pattern with bright colors, and very long and flowing fins. In contrast, a healthy, standard Koi that comes from a reputable breeder might be the same expense as a Butterfly Koi without any extra special features.

Butterfly Koi vs Standard Koi

Butterfly Koi are different from standard Koi because of their fins, where Butterfly Koi have fins that continue to grow longer over their lifetime. As a result, they have long, flowing fins, whereas standard Koi have fins that stop growing after a certain point. Butterfly Koi also tend to have more slender bodies than their standard Koi counterparts.

Fish Laboratory

With decades of collective fishkeeping experience, we are happy to share the fish care tips that we've picked up along the way. Our goal at Fish Laboratory is to keep publishing accurate content to help fishkeepers keep their fish and aquarium healthy.

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