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15 Koi Fish Facts you must know today

Koi fish is a stunning creation of nature and they have already invaded the whole world. Japanese believe Koi is a symbol of luck. However, this domesticated variant, Koi fish colored your aquarium and also, bring fortune to your life. There are so many Koi Fish Facts you should learn.

15 Koi Fish Facts you must know today

After reading this article, definitely Koi fish become a member of your aquarium. You can find out koi fish meaning in the global koi center.

Koi fish care facts

Size (How big do Koi get?)

When you feed and care for your Koi fish properly, they grow about an inch a month and up to 9 inches by the end of the first year. Generally, healthy Koi eat and grow up to about 20 inches or more in captivity. But how large your Koi fish depend on several factors.

These factors are their specific or genetic makeup and the aquatic conditions in which they live. As an example,

  • Domestic Koi – usually grow up to 12-15 inches in length.
  • Japanese Koi– grow up to 22-26 inches.
  • Jumbo Koi– can be as big as 36 inches.

Comparing other fish, Koi fish grow rapidly and they take around 3 years to grow full adult length.

koi fish FACTS NEW

Native habitat

Wild koi fish are native to the freshwater around the Black, Caspian, and Aral Seas. In the 19th century, Japanese farmers caught wild, colorful Koi and bred them. Today there are different colors of Koi. Though the Japanese had introduced the domesticated koi, now these fish are in throughout the world.

Food/eating habitats Koi Fish Facts

Koi fish are omnivorous. It means koi eat both animal and vegetable matters. They eat foods that can be found at the bottom of the water. Koi eat microorganisms such as algae, zooplankton, insects, and also plants in your tank.

Furthermore, your Koi likes some human foods like cereal, lettuce, shrimp, rice, peas, and watermelon. Also, people normally give fish foods that are prepared specially for domestic Koi fish such as pellets and flakes. Through these foods, people try to fulfill all the nutrient needs of Koi fish.

Reproduction and development

Koi fish spawning or breeding behavior occurs once a year and it happens most probably in late May to late June. Spawning is beginning when the preferable conditions such as temperature, water quality, and other conditions are right.

Usually, spawning is beginning early in the morning. In this time you can see, that males aggressively chase the female Koi fish. Male koi follow the female koi fish until the eggs are released by the female. As soon as the female Koi fish lays eggs, the males fertilize them. When female Koi fish shed the eggs, they stick to substrates that will connect with the eggs first. Matured female Koi fish have the ability to produce about 400,000 eggs.

Credits to Giobel Koi Center


The Koi fish can live from 20 to over 200 years. Generally, the average lifespan of Koi fish is about 40 years.

It is believed that the oldest-known Koi lived about 230 years old. A female koi fish named Hanako lived a long time. She lived for approximately 226 years. Scientists calculated Koi fish’s age by examining the rings on the scales of particular Koi fish. However, genetics, nutrition, water quality, and environment are the factors that directly affect the lifespan of the Koi fish.

koi fish FACTS

Can koi live with other fish (tankmates)?

When you chase the tankmate for your Koi fish, there are several things to consider.

  • The first thing to ensure is that the fish is not aggressive and will not attack your Koi fish. social and friendly fish are good tankmates to your Koi.
  • it is better to choose the fish as a tankmate that similar to the size of the Koi fish
  • The temperature requirement should be the same. Or, at least the selected fish should be able to grow at ambient temperature for Koi
  • Make sure the selected fish does not need more care than the koi, as it is difficult to meet their requirements.
  • Selected fish should not fight with Koi fish for food.
  • It is better if the selected fish species is a bottom feeder.
  • It is better if the selected species have similar characteristics to Koi fish

There are many fish species that can live with Koi fish in the same tank.

  • Barbel (Barbus barbus)
  • Barbs (Barbus tetrazona)
  • Catfish (Siluriformes); Bandit Cory Catfish, Bumblebee Catfish, Columbian Shark, Iridescent Shark
  • Goldfish (Carassius auratus)
  • Golden Orfe (ILeuciscus idus)
  • Tench (Tinca tinca)
  • Pleco (Hypostomus plecostomus)
  • Sturgeon (Acipenseridae)
  • Color variations of the Koi fish

Koi fish can find in various colors, white, red, black, blue, yellow, and cream colors.


  • Kohaku – this Koi fish has an attractive white color with red spots
  • Taisho Sanke – presence three colors, white, red and black on the body of this Koi fish
  • Showa – this fish has a color combination of black, white, and red.
  • Tancho– It is snow white and has a dark red spot on the head.
  • Utsuri – this Koi fish has a black-colored body with white, red, or yellow marks.
  • Bekko – Koi fish has a red, white, or yellow-colored base with black markings.
  • Asagi – They have a blue-colored pattern on the upper part of the body and a reddish-orange color on the belly, fins, gill plates, and body.
  • Koromo or Goromo– The body of a Goromo koi is white with a reddish-orange pattern

Koi fish fun facts

The main misconception is that koi are large goldfish. Both Koi and goldfish are domesticated from carp but they are very different species from each other. Although carp are popular among anglers, Koi are bred for ornamental ponds. Koi and Goldfish are the most popular freshwater, ornamental fish in the world.

While the breeding industry can be quite lucrative, there are rumors that individual-show-quality Koi fish can sell for hundreds of thousands of dollars.

Read more Can I Keep Koi and Goldfish In the Same Tank? All To Know

Interesting Koi fish facts

Koi pond –

You can find this beautiful fish swimming in the pond. These ponds have become popular all over the world for this reason. you can find these amazing fish species all over the world.

Cold climates –

Amur carp live naturally in cold water. This is why there is such a strong attitude to domestic variability. It grows in outdoor ponds, even in the coldest areas

Japanese culture –

The Japanese consider the Koi fish as a symbol of love and affection.

Koi goldfish –

Humans have produced Koi goldfish quite recently compared with goldfish. The development of Koi goldfish began in the early 1800s, but humans began to breed goldfish thousands of years ago.

Frequently asked questions Koi Fish Facts

What is special about Koi fish?

Koi fish is the ornamental version of the carp. In many Japanese cultures, koi represents material or spiritual abundance or development. Koifish always moves easily in the water when the tide flows under the water. Koi has mind-blowing color variations with various patterns and flowing fings.

Do Koi fish recognize their owners?

Yes. Koi fish have the ability to recognize their owners of them. There is a high probability of happening if the owner feeds them regularly.

Koi fish are extremely intelligent fish. but if you want to experience this, you as the owner of the Koi fish should spend enough time with your koi to gain their trust.

Can Koi live in fish tanks?

Koi fish can live in a tank. But when you keep Koi fish in a tank, you have to face different challenges than other fish species. The reasons for this challenge are their size and messing behavior. Therefore you should set up your tank considering the sizes of your Koi fish.

When you set up the tank you must concern the several factors such as temperature, filtration, lighting, oxygenation aquatic and, etc.

How much does it cost for a Koi fish?

The average price of most Koi is around $ 50, but it can be much higher (thousands of dollars). The price can be varied with genetic lineage, size, coloration and pattern and etc.

Can koi fish live 200 years?

According to reports, koi fish can live longer under optimal conditions, and there are many koi that live for more than 100 years. But most parts are considered rumors and most koi only live for a few decades. However, the oldest lived more than 200 years and its age was scientifically verified.

What is the rarest Koi fish?

Ki Utsiri is the rarest Koi fish. This Koi fish has a lacquered black body with patterns of yellow.

Why is Koi fish good luck?

Feng Shui, a spiritual form of organization and object placement, says that having a Koi spirit with you, brings good luck, fortune, and spiritual benefits. Because the Chinese word fish (yu) sounds like “surplus”, it represents the overflow of luck.

In addition, Koi fish are in the water and according to Chinese belief, water symbolizes wealth and prosperity.

Read More How long do koi fish live? How to make them live longer

Can you eat Koi?

Koi are a specialized subspecies of Asian common carp, and they are not poisonous, so yes, Koi can be eaten technically. Eating koi fish can be experienced as eating carp.

Credits to Carl and Alex

Further reading

Optimization of stocking density of koi carp (Cyprinus carpio var. koi)

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About Dr.Chamika

Hello, I'm Dr. Chamika. I am a Researcher in Water quality, Aquatic organisms, and Environmental chemistry. I am a passionate fish keeper, with10 years of experience. My mission is to help other aquarists experience the joy of fish keeping.