April 6

Sarah Robertson

What Is Special About Koi Fish?

Koi fish are a domesticated form of the common carp or Cyprinus carpio. They are kept for ornamental purposes in outdoor ponds, aquaria, and water gardens. Koi varieties are distinguished by coloration, shapes, and scale patterns. Koi may simply be mistaken for an enormous goldfish, but they are not related in any way.

Koi fish are considered very special. In fact, they are one of the most expensive pets to keep. A koi's worth is determined by a variety of criteria, including color, design, quality of fins, and body form. So what exactly sets these fish apart? A lot, in fact!

What Is Koi Fish?

Koi are a colorful ornamental variety of fish that come from the carp. They can be found all over the world, but what makes Koi so special is their coloring and lineage. These fish species come in a wide variety of colors, patterns, and sizes.

They have a different variety of color cells in their skin. Their major color cells can be red, yellow, black, white, blue, or metallic.  Although the range of colors is virtually infinite, breeders have established and named a number of categories.

They are popular in outdoor ponds and water gardens because they bring both color and life to the area. While they are related to the common species of carp, koi are not goldfish. In fact, koi are considerably more expensive to keep as pets.

Why Are Koi Fish So Popular?

Koi fish are beloved pets in any environment with a beautiful appearance. They provide beauty and relaxation in every situation. They've been kept as pets for thousands of years in China and Japan.

They've won the hearts of millions of people all around the world, starting in China and Japan. The colors and designs of koi fish are breathtaking. In Asian culture, every color in a Koi's rainbow is significant. There are several different reasons why Koi fish are so popular, notably among home aquarium owners.

Colors Have a Significant Influence

The popularity of Japanese Koi fish stems from the fact that they have been carefully bred to match a specific color and size for hundreds of years. In Japanese culture, each colored Koi has a meaning.

  • Golden Koi: They stand for financial gains, success, and greater development.
  • Red and White Koi: Kohaku Koi is another name for the red and white Koi. It represents love, care, and good fortune in personal relationships.
  • Ochiba Koi: The Ochiba Koi symbolizes the passing of one season to the next. Its name, "Ochiba," is a translation of the Japanese term for "leaves falling in the water." Its back is blue-grey with a brown pattern (it resembles dead, fallen leaves).
  • Platinum Koi: There is a platinum-colored Koi. It's also known as the renowned "Ogon Koi." The Ogon Koi is a symbol of money and success in one's career.
  • Dragon carp: It is the name given to the butterfly Koi. They have elongated fins, like dragons. They are the outcome of crossbreeding ancient Koi with wild Indonesian longfin river carp. They represent good luck and fortune. They also stand for beauty, charisma, and refinement.

The color of the Koi fish should be consistent across the entire fish's body. While Koi might have a variety of colors, each color should have similar intensity and consistency. The different hues of the fish should all be the same color. This implies that the blacks should not be black and grey, but rather pure black. Keep in mind that as the Koi mature, their colors will alter.

Koi Body Shape and Size

Koi Body Shape and Size

Koi fish are characterized by their distinctive appearance. They come in an array of colors, shapes, and sizes. Some are long and thin, while others are short and stocky. When looking for a koi fish, make sure the head is long and broad. The eyes should be set at equal distances apart and at the same level. Koi fish symmetry is one of the most important aspects when it comes to selecting Koi fish.

The size of koi ranges from just a few inches to over three feet long. In general, the larger the koi, the more valuable it is. The length of a domestic Koi is typically 12 to 15 inches.

Japanese Koi fish grow up to 22 to 26 inches long. Jumbo-sized Kois can reach a length of up to 34 to 36 inches. The most frequently asked question of all time is whether the size of your pond will influence the size of Koi you can keep. The answer is ‘NO’; the size of a pond will not stop these cold-water fish from growing.

Koi Pattern and Age

The beauty of Koi fish patterns is largely determined by balance. Even distribution of design that is appropriate to the size of the fish is ideal. If a big Koi has a tiny pattern, it might appear as though something is missing from the fish.

A small Koi, on the other hand, feels overwhelmed if there are too many patterns. The goal of patterning that covers the fish uniformly is to offer a well-balanced visual appearance. When the nose and tail of a Koi fish are the same hues, it feels well-balanced, and the colors and patterns that exist in between feel framed.

Koi can live up to 20 years, although the typical lifespan is around 50 years. You won't be able to determine a koi's age unless you look at specific aspects such as the size of its ear bone or the number of tiny rings on certain metallic scales. There are many factors that affect a koi's lifespan. Some of them are:-

  • Genetics
  • Nutrition
  • Water Quality and Environment
  • Wintering

Some Koi Fish Facts 

Even if you have a wealth of knowledge about koi fish, there are always more fascinating koi fish facts to learn! There's a lot to learn about how koi fish came into existence, their habitats, features, koi fish meaning, feeding, behavior, and species.

Koi Fish Meaning

The koi is a symbol of luck, wealth, and good fortune in Japan, as well as perseverance in the face of adversity. The ornamental koi are representative of Japanese culture and are closely linked with the country's national identity.


Nishikigoi, sometimes known as Japanese Koi fish or Japanese carp, are brightly colored and patterned fish that are kept as a hobby. The carp is native to China, where it was acquired as a present from the Chinese people.

In the 16th century, Chinese farmers cultivated carp in rice paddies, a practice that was later taken to Japan and refined there by the Japanese, who noticed color variations in some of the fish and bred them.

The first koi fish to be sent to Japan was delivered to the king. Later, Japanese koi fish were used as a source of food. However, due to their beauty and considering how expensive it was, they were no longer seen as a source of food but rather as a symbol of wealth and status and were used for decorative purposes.

Since then, these coldwater fish have been bred in a variety of combinations of all colors in the rainbow since they were originally only available in red, white, black, and blue.

Habitat of the Koi

Habitat of the Koi

The Japanese koi is a fish bred through selective breeding of various carps, such as goldfish, to produce the colorful species. As a result, there is no one definitive koi habitat.

The parent fish of the koi species is Cyprinidae, which may be found in every region of the world's freshwater. Cyprinus carpio, on the other hand, is a Chinese native that has now been dispersed throughout the world. Koi become very large and grow quickly. Mature koi should be kept in an outdoor pond with at least 3 feet of depth and at least 500 gallons of water per fish.

Small koi can be kept in an aquarium with a capacity of at least 29-30 gallons. The ideal water temperature for a koi pond is between 60 and 75 degrees Fahrenheit (16 and 24 degrees Celsius). It is also important to locate the koi pond where there is both shade and sunlight in equal ratios.

When koi are exposed to both sun and shade, they thrive and increase their survival rate. This enables them to maintain their own body temperature and avoid getting too hot or cold. Koi fish can even live well in winter temperatures as they are coldwater fish.

Koi Fish Characteristics

You know a Koi fish when you see one! The lifespan of these beautiful fish is around 30 years. Some people, on the other hand, are thought to have lived for as long as two centuries. In the right environment, koi fish may reach up to two and three feet long.

In rare cases, Koi Chagoi koi fish has been discovered to grow up to four feet long. The body of a Koi fish is robust and then slender on the sides. They have a small mouth and teeth that are arrayed in three rows. The spine of the fin on their back is elongated and sunken, with the tip closed.

They have huge scales; their color is greenish-brown with golden and bluish reflections and a whitish belly. Finally, it is understood that a koi fish is healthy when it is neither too energetic nor passive.

Diet of the Koi

Japanese koi fish are considered omnivorous fish but in the wild, koi fish consume algae, greenery, insects, worms, seeds, and anything else they can find on the pond's bottom. They stalk across the floor of the pond as well as over its surface.

If you have an ecosystem pond like this one, they may continue to eat like in nature. Koi are fed a diet of foods that may be consumed by humans. Shrimp, fruit, vegetables, and other meals with little carbohydrates are some examples. Some of the foods that koi enjoy include spirulina algae, wheat germ, brine shrimp, fish food, earthworms, larvae, tadpoles, shrimps, and clams.

The Behavior of the Koi

Recognizing your koi fish and how they interact with their environment is important to koi keeping. Recognizing patterns of behavior throughout the year can help you understand your pond. It might also keep your fish healthier and happier, as well as allow you to diagnose any issues quickly. Here's a list of the many types of fish behavior.

A Friendly and Healthy Koi

Koi is a peaceful friendly fish. When they first arrive on your pond, they may take some time to get acclimated and acquainted. After quarantining your koi, establish a feeding plan and stick to it. After your goldfish have adjusted to their new surroundings and you, they will become friendlier.

Make sure to sit by the pond when feeding them so that they learn to know you. Koi that have established a rapport with their keepers will come to the front of the pool and eat out of their hands. They may even leap from the water as you pass by.

Stressed koi

When stressed, koi fish act strangely. They dislike sudden changes, especially if they're being moved into a new pond or tank or exposed to fast water temperature swings. A koi who is anxious may skip a feeding by hanging around the pond's floor.

They might become standoffish and lethargic. Koi that are feeling stressed will jump or paw at the pond's boundaries. Koi’s' fins may also be affected by stress. The edges of their fins could appear bloodshot or tattered.

There are a number of circumstances that might cause koi to be nervous. They might be in danger from predators that lurk outside the pond. Fertilizer runoff into the water may have caused pollution.

The answer may lie in the pond. To ensure that all chemical requirements are met, do a water test. This may also be stressing your koi out of the pond is overcrowded.

Sick koi

Stress can harm the immune system, causing ill health in a stressed koi. There are several significant symptoms of the disease that appear when your koi fish is sick, although each condition has its own set of symptoms to look for.

The behavior of your koi fish is another indication of the illness. If they are zipping around the pond or acting strangely, they may be ill. They may be unwell if their formerly graceful swimming has become clunky and chaotic.

Leaping koi

If your koi are leaping up or gasping for air at the surface of the pond, there may not be enough oxygen in the water. Consider various sources of oxygenation. Start by performing a partial water change, then clean the filters and vacuum out any debris.

If the pond is very deep and has a small surface area, adequate oxygen may not be entering and circulating throughout the water. To naturally aerate the water, consider expanding the pond or adding a waterfall or fountain. Water in an oxygen-deficient state will not be able to effectively support the growth of healthy aquatic plants, resulting in their collapse. Signs that your koi pond is devoid of oxygen include algae growth and foul odors.

Koi Fish

Koi Fish Varieties

The hobby of millions today, the koi is more than just a cultural icon but also an inquiry into charm and variety. The solid black-colored carp is the common ancestor of all different types of koi. The Japanese are credited with being the first koi breeders and enthusiasts.

The food requirements, low upkeep in terms of water quality, oxygen levels, and nutrition attracted the Japanese people to raise koi carp fish. As time went on, the Japanese farmers became enthralled with the wide variety of koi. As a result, selective breeding began, resulting in bright beautiful colors, scales, and patterns. Today, there are almost a hundred distinct varieties of koi, each with its own pattern, color, and form.

  • Hariwake and Kikusui-Hariwake is a relatively new variety of orchids that has come to prominence in recent years. It has a bright white metallic base color and is often confused with Kohaku. Hariwake may be defined using yellow or orange hues, unlike Kohaku. Kikusui is the Doitsu name for a Hariwake; Tancho is the only difference. Hariwakes are available in two varieties, Tancho and Gin Rin.
  • Goshiki- Goshiki means‘5 Colors and it has a sturdy foundation of white enhanced with blue and black edging. A red-blue design will overlay the white, black, and blue background. Gin Rin and Tancho varieties are available.
  • Goromo- Goromo, like Kohaku, has red scales that are patterned similarly. Goromo distinguishes itself from Kohaku by displaying a blue or black edge to its red scales. Each Goromo has 3 variations: The Ai Goromo has a blue edging to the interior of the red scales, the Budo Goromo has a blue edge to the outside of the scales, and the Sumi goromo has a black edge to its scales.
  • Soragoi- Like Chagoi, Soragoi is a docile fish that learns to hand-feed in a pond first. They are identified by their solid grey or silver scales, which are highlighted with webbing throughout the body.
  • Hi Utsuri and Ki Utsuri- The colors of these Koi are comparable to those found in Shiro Utsuri, although the colors are deeper and more vibrant. The skin is black with deep red or orange patterns overlain. Reds are regarded to be of higher quality than oranges, but most juvenile fish will have an orange coloration. The body of the Kintaro is in a striking yellow color. The Gin Rin and Doitsu versions are available.
  • Tancho Kohaku-The Tancho Kohaku, also known as the red-belly koi, has a solid white underbelly and are recognized for their distinctive red mark on top of their head. Hobbyists seek after these because they are an uncommon type among koi.  These beloved pond fish species may be found in Gin Rin and Doitsu types as well.
  • Kujaku-Kujaku is a stunning single made up of a black net pattern on top of a solid white background and highlighted with bursts of red, yellow, and orange. The black border generates the net design by encompassing each scale's edge. Doitsu, Tancho, and Maruten are three options for this product.
  • Shiro Utsuri- A beautiful koi with a black base dotted in white spots. The blacks should be a rich, dark color, as they were in Showa. An even ratio of blacks and whites should be evident on the head. The line between black and white portions of the fish should be crisp and free of bleeding of color. Gin Rin and Doitsu types are available.
  • Ochiba Shigure- Shigures sometimes referred to as Shigure, are a group of Japanese koi that combine Chagoi and Soragoi's browns and silvers. They'll also exhibit similar qualities to those species, such as their eagerness to feed and relax other koi. Autumn leaves drifting down on a lake translate to "autumn leaves floating in the water" in Japanese. They are available in Gin Rin and Doitsu variants.
  • Ogon- There are two distinct colors of Ogon: Platinum and Yamabuki. Platinum is a solid, metallic-white hue, while Yamabuki is a solid gold color. The color must be pure and flawless throughout the body and head in both versions. Gin Rin and Doitsu are two of the many types.
  • Shusui- These are actually the scaleless or Doitsu variety of Asagi. Instead of having the blue netting along their backs, this is replaced with a single row of deep blue scales along the dorsal line. As with Asagi, the rest of the fish should display a solid red pattern throughout. They are available in Gin Rin and Hi Shusui variations.
  • Taisho Sanke- The Sanke is a type of koi that has a red and black pattern over a pure white base. The color should not be yellow, and the reds and blacks should be well defined. It's not unusual to find blues in developing black specimens, but they should darken as they get older. They are available in Doitsu, Maruten, Gin Rin, and Tancho types.
  • Kikokuryu and Kin Kikokuryu- This is a Doitsu variant of koi that has a white base with black spots within the scales. They may also have black markings on the back row of scales and around the head, eyes, and nose. Flashes of orange and yellow markings are also possible in Kin Kikokuryu.
  • Showa Sanshoku- Showa is a black Koi with red and white markings. For a high-quality Showa, you'll need a strong definition with no bleeding of hues. These are available in Doitsu, Maruten, and Gin Rin varieties, much as the Sanke.
  • Kohaku- Kohaku is regarded as the most ancient and well-known koi variety. Kohaku has a white foundation with a red pattern overlay. Kohaku of high quality should have a distinct line along the crimson boundaries, as well as vibrant reds. Kohaku comes in a variety of forms; two steps (Nidan), three steps (Sandan), four steps (Yondan), and Inazuma, which is a lighting 'zig-zag' pattern down the backs of the fish. Doitsu, Gin Rin, and Maruten are additional kinds.
  • Asagi- The most popular Koi varieties are readily available on the market. The Asagi fish is recognized for its deep blue netted pattern on its back. Red or orange highlights are used to accentuate the belly, body, gill plates, and head. The Asagi must have a red or any hue that is above the lateral line, which serves as a distinction between the blue netting on the back and the red body color. Gin Rin and Hi Asagi are two options.
  • Kumonryu and Beni Kumonryu- Kumonryu is a fun fish to have in any pond since it will alter its pattern several times throughout its existence. The Beni form of Kumonryu will be grey, white, or black, while the Doitsu type will show reds. Their color can range from completely black or white to every hue several times throughout their lifetime.
  • Chagoi- Turquoise koi is one of the most popular Koi species since they're recognized for their ability to soothe other types of koi and are frequently the first to be trained to hand-feed - enticing others to do likewise. Chagoi have a net-like pattern on their back or body that is dark brown or bronze in color.
  • Matsuba- Doitsu Matsuba is another of the few koi that has only one variation. They have a solid metallic foundation with a black net design, which is prominent along the back but visible throughout the body in some cases. The base should be silver in color, although it may vary. Gin Matsuba is white, Aka Matsuba is red, and Ki Matsuba has yellow markings.


Why are Koi Fish so Expensive?

Koi are among the most valuable fish in the world. The most expensive koi fish ever sold was worth $1.8 million. Koi are actually a kind of carp, and today they're one of the most expensive pet fish in the world.

But why is it so? Koi were originally cultivated in Japan throughout the 1700s by rice farmers who wanted to breed them for their distinct hues and designs, similar to how we develop dogs for their particular characteristics. Koi breeding is also highly regarded among Japanese people, just like other rare dog breeds.

There are numerous contests to select the greatest koi. The fish's skin tone, size, and shape as well as how elegantly it moves in the water are all considered by judges and purchasers. The most essential feature, however, is the koi's color. According to their kind, the ideal koi have a good mix of colors and patterns.

Koi Fish Live

How Many Years Does a Koi Fish Live?

In captivity, koi may live up to 20 years on average, although the typical lifespan is around 40-50 years. You won't be able to determine the age of koi unless you look at certain features such as the size of its ear bone or the number of tiny rings on specific scales.

Can You Eat a Koi Fish?

You can eat koi. But most people wouldn't want to as they are considered sacred in places like Japan and a good luck omen in other countries in South East Asia. Also, koi meat, like all other carp, is a bit tough. Koi spend much of their time in shallow, stagnant water, so the risk of picking up a bacterial infection from them is high.

Finally, these fishes are sold as decorative, ornamental, or sacred fish, to be kept as pets. The animals are also bred for their exotic body patterns and colored markings. Due to all this, most koi are captive bred. And these go for pretty high sums apiece alive, even up to a thousand dollars or more.

How Big Can a Koi Fish Get?

The average length of a domestic Koi is around 12 to 15 inches. Japanese Koi grows up to 22 to 26 inches in length. Jumbo-sized Koi can reach up to 34 to 36 inches long. 

Do Koi Fish Like to be Pet?

Koi are also tolerant of other fish and will come up to the surface to say hello when they see their owner or it's time to eat. Some koi even enjoy being stroked and will surface to accept a comforting pat on the head. As a result, koi are considered one of the best "starter fish" for children or first-time pet fish owners.

Are koi fish difficult to maintain?

It's not difficult to take care of koi fish, but there are several issues to consider. The most essential aspect is maintaining their water clean, balanced, and aerated. They can endure the winter and are omnivores that feed on a variety of foods.


Koi are beautiful, majestic creatures that have been revered by both Japanese and Chinese cultures for centuries. These stunning fish come in a variety of bright colors and patterns, and their peaceful nature makes them a popular choice for pet owners and pond enthusiasts alike.

They are not difficult to care for and can thrive in both normal and cooler temperatures. However, koi do require some special considerations when it comes to their diet, housing, and water conditions. With a little bit of knowledge and care skills, you can enjoy these amazing animals for years to come.

Sarah Robertson

I am a passionate blogger who also happens to be a fish keeping enthusiast. Writing about my hobby is something that I absolutely love to do, and it's no secret that my chosen topic is always centered around fish keeping.

Sarah Robertson

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