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Black Koi Fish: Facts, Origin & History (With Pictures)

Koi or “Nishikigoi” can be found in a range of different colors, and many koi varieties have black markings or a solid black coloration.

These are ornamental fish that are commonly kept in ponds or water gardens, and their hardiness allows koi to thrive in conditions many other aquarium fish can’t. Koi have a rich history in Japanese and Chinese culture and are a symbolic fish that bring good luck and prosperity. Owning one of these fish has become popular around the world, with the origins of the koi’s ancestors originating in China.

Length: 20–36 inches
Weight: 9–16 pounds
Lifespan: 25–35 years
Colors: Black
Suitable for: Large freshwater ponds
Temperament: Peaceful, intelligent, and social

Even though many koi have black pigments mixed into reds, oranges, or whites, there are only one koi that has a solid black color. This would be the Karasu koi fish, which is a variety of koi. A “black koi” is not a true variety of koi fish, and it is used to describe koi fish with black colorations.

The black markings or colorations are typically referred to as “Sumi”, and certain solid black koi might be called Sumi koi. Sumi refers to a type of black Japanese ink, which is why it has been used to describe the black markings on koi. Black koi fish are most popular in Japan since the Japanese produced the solid black Karasu koi fish.

Black Koi Fish Characteristics

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The Earliest Records of Black Koi Fish in History

The Asian continent is the birthplace of koi fish, with records of the koi’s ancestry fish dating back to AD 200 in China. Koi fish descended from Amur carp, which are a type of freshwater carp that developed color mutations and were called brocaded or colored carp. Koi originates from China where their ancestors the brocaded carp were first domesticated, but the Japanese were the first to selectively breed these prized fish for their colors and patterns.

Fossils of the carp date back millions of years ago from when they inhabited the Caspian, Aral, and Black seas. These carp were initially kept as a food source for agricultural purposes in both China and Japan, but the Japanese took interest in breeding them for more than just food.

At some point in time, the Chinese rice farmers noticed that the koi developed natural color mutations, such as reds, whites, blues, and black. During the Shang dynasty in China around 1600 to 1046 BC, the carp were raised in ponds and viewed by royalty as a form of entertainment. Since then, there has been plenty of literature and artwork mentioning koi fish, including ancient paintings that depict beautiful Nishikigoi.

Black Koi fish in a pond
Image Credit: blt 99, Shutterstock

How Black Koi Fish Gained Popularity

The carp were introduced into Japan after China invaded Japan. The koi fish selective breeding in Japan dates back to the early 1800s, between 1820 and 1830. Black carp known as “magoi” could be found in the Niigata waterways in the 1600s before being caught by farmers. The Japanese villagers of Ojiya saw potential in these mutated carp and began to breed the red and white colored koi for ornamental purposes.

This led to the carp being named “Nishikigoi”, meaning brocaded carp. The koi gained popularity in Japan after being recognized for their colors which weren’t common in fish at the time. This was the start of the many koi fish varieties available today, and it led to the development of the black (Sumi) pigmentations on koi fish.

When Did Black Koi Fish Become Recognized As Pets?

It wasn’t until the early 1900s that koi fish became more recognized, which would eventually lead them to become pets. Although the koi were being bred to produce more vibrant colors, the Japanese weren’t marketing them as pets. When a koi fish was gifted to Emperor Hirohito in Japan for his imperial palace moat in 1914, koi started to become more recognized.

Other parts of the world became to take an interest in these beautiful and elegant fish, leading to their distribution as pets outside of Japan. Since black pigments on a koi were common in many varieties, some of the first pet koi fish likely had black patterns on their bodies. The Karasu, which is a solid black koi fish, was developed by Japanese koi fish breeders and is now kept as a pet around the world.

white koi in between two black koi in the water
Image Credit: es3n, Shutterstock

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Top 4 Unique Facts About Black Koi Fish

1. Karasu koi are the only koi to have an almost solid black coloration.

While black is not an uncommon color to see in koi fish, any koi that have a truly solid black color aside from their underside are Karasu koi. These koi have an inky black color that covers most of their bodies. The Karasu koi is monochromatic when viewed from above, which makes them look striking in ponds and water gardens. In recent years, the Karasu has become quite popular in koi kichi ponds.

2. Karasu koi are not magoi.  

Karasu is often confused with magoi since both fish have a black coloration. However, magoi do not have the true black coloration like Karasu koi fish do. When compared to dark backgrounds, magoi will look browner whereas Karasu will maintain a black-hued body.

one white fish with multiple black koi in the pond
Image Credit: es3n, Shutterstock

3. Black koi symbolize good luck and positivity.  

Black koi fish symbolize good fortune, strength, and determination. In Japanese culture, their dark black bodies are believed to absorb negative energy and evil entities. People also keep black koi in ponds with other vibrantly colored koi to protect them from evil and keep the koi in good health.

4. Karasu koi are not found scaleless.

Although Karasu koi fish can be found with butterfly or regular fins, they can only be found with scales (wagoi). If the fish has a black coloration and has no scales (doitsu), they are probably a Kumonyru koi that has turned black.

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Do Black Koi Fish Make a Good Pet?

Black koi fish like the Karasu makes excellent pets. Just like other koi, they do best in a large pond that is filtered. The water should be kept clean through the filter and regular pond maintenance. If the pond becomes murky, it will be difficult to see your black koi fish.

A black koi fish’s care is the same as any other koi, and a healthy diet and good water quality is the key to keeping your koi fish healthy. Your black koi needs a pond that holds at least 1,000 gallons of water or more since they need to be kept with other koi fish.

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The black coloration on koi fish looks mesmerizing when they are kept with colorful koi varieties. You can find the black pigmentation on parts of koi fish to form a pattern in combination with colors such as white and orange, or it will be a solid coloration in Karasu koi. With such fascinating origins, striking coloration, and peaceful temperament, it is clear why koi make such popular pond fish.

Featured Image Credit: JuanCarlosPalauDiaz, Shutterstock

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