What Are Koi Fish?

No doubt you have heard the term koi fish or even seen some of them in an ornamental pond. But what exactly is a koi fish and where do they come from? 

What are Koi Fish?

Koi fish are a colorful, ornamental species of fish that were selectively bred from common carp in eastern Asia. They come in a variety of different colors to include orange, red, yellow, black, white, and blue. Koi fish are a large, long-lived, gregarious fish that are prized by people across the world. They also have deep symbolic meaning in many Asian cultures. 

There are many different koi varieties with various colors, patterns, and shapes. All of these originate from the original Japanese Nishikigoi.

Where Do Koi Fish Come From?

The koi fish we know today come from Japan, but the origin of koi fish likely began in the 5th century in China. At this time in ancient China, the Amur carp (Cyprinus rubrofuscus) began to be domesticated as a food source. These were hardy cold-water fish and this allowed them to thrive in a variety of different places. Due to their hardiness and utility as a food source, their domestication spread to other places like Japan. 

It wasn’t until they reached Japan that they began to be bred for their ornamental traits rather than food. While most of these early common carp were dull black color, genetic mutations led to a small number of fish with more coloration. It was these fish that were selectively bred to create the koi we have today. 

The breeding of these colored ornamental carp first occurred in Niigata Prefecture in Honshu Japan in the early 1800s. These fish were originally known as Nishikigoi” and later as koi. It wasn’t however until 1914 that the outside world was introduced to these fish at an annual exposition in Tokyo. 

Why Are Koi Fish So Popular?

Koi are a popular ornamental fish for a variety of reasons. 

As mentioned previously they are an easily adaptable cold-hardy fish. This means that they can be kept in a variety of climates and conditions. Smaller koi can be kept indoors in an aquarium and larger koi in outdoor ponds. With proper care, they can even be kept in an iced-over outdoor pond during the winter. 

Koi Pond with koi fish, plants and waterfall

These outdoor ponds are known as “koi ponds” and are a sight to behold in their own right. With beautiful decorative stone, plants, and other décor they become a focal point of any garden. People spend many thousands of dollars installing and maintaining their koi ponds. They range in size from a few hundred gallons to tens of thousands. I believe that the koi pond is part of the allure and one of the reasons koi fish are so popular.

While a beautiful koi pond complements the koi in it, it’s the koi themselves that are the stars. Their bright array of colors, patterns and impressive size make them a sight to behold. Very careful breeding goes into the most prized and expensive koi. True to their historical roots the Japanese breeders have the best and most expensive koi. One of these Japanese koi sold for a jaw-dropping 1.8 million dollars!

Aside from the aesthetics of koi or koi ponds, koi fish have great personalities. They are naturally very social and gregarious. Their peaceful demeanor and graceful swimming make them a joy to simply observe. They can also be trained to eat right out of their owner’s hands! How cool is that?

Final Thoughts

Koi fish are in a category all their own that no other domesticated fish can match. Their beauty, size, history, and personality make them unique in the fish world.