Koi Fish

Koi fish have fascinated their owners and brightened their ponds for hundreds of years. People who have some money in the bank aren’t shy about paying great sums for a champion fish of noble lineage. There are 16 main types of koi, each with its own pattern of colors. Read on for more information about these remarkable fish.

5 Incredible Koi Facts

• Japanese rice farmers started breeding koi for their beautiful colors in the 19th century.
• Koi have different meanings depending on their coloring. For example, the Ogon koi with its metallic silver scales is a symbol of wealth and a successful business.
• Both goldfish and koi are descended from the carp, a fish whose favorite habitat is a body of standing water with a muddy bottom. Koi have a faster growth rate than goldfish, but the two can interbreed. However, their offspring are sterile.
• The longest-lived koi was a beautiful scarlet fish named Hanako. She was 226 years old when she died, and people could tell because the rings on her scales indicated her growth rate.
• Koi fish thrive in cool water with a pH level between 7.0 to 8.5. Water with a pH level much below 7.0 or much higher than 8.5 might kill or sicken the fish.

Classification and Scientific Name

The scientific name of the koi fish is Cyprinus rubrofuscus “koi.” Cyprinus comes from the Greek kyprínos, whose meaning is “carp,” and rubrofuscus means something like “reddish dark brown” in Latin, which describes the animal’s coloring. So the fish’s scientific name is a “reddish dark brown carp, koi version.”

Origin

Accounts of Japanese emperors possessing prized ponds of brilliantly colored carp appear as early as 720 AD. Concerted efforts to breed these fish and their later classification as koi did not occur until much later, sometime in the early 1800s. This was achieved by selectively breeding Amur carp that expressed particularly striking patterns. Over the course of the 19th Century, certain varieties became immensely popular, and an entire subculture surrounding koi breeding arose. This practice is still thriving today and has spread outside of its native Japan to fish enthusiasts around the world.

Appearance

A koi fish should be torpedo-shaped and symmetrical, with no defects in its conformation. It should be plump without being obese, and the paired fins should be the same shape and size. Koi have a subterminal mouth, located slightly underneath the head and facing downward, which is typical for bottom-feeding fish. Barbs are found at the edges of the mouth, which gives away the koi’s carp ancestry. The colorations of all types of koi fish should be rich and saturated, and white and silver scales should have a sparkle to them.

How Much Was the Most Expensive Koi Fish Ever?

The most expensive koi fish ever sold was for $1.8 million. It was a female red and white koi fish named S Legend whose owner waited until she was nine years old to sell her. S Legend was 3 feet 3 inches long. She was prized for her perfection of form, her brilliant, perfectly distributed pattern of red and white coloring, and her lineage. She was a Kohaku variety of koi. Kohaku simply means “amber” in Japanese and is the oldest koi type. She was sold to a mysterious Miss Yingying of Taiwan.

Distribution, Population, and Habitat

People around the world keep koi fish in their water gardens. They are also found in zoos such as the San Diego Zoo, Japanese gardens such as the one at the Brooklyn Botanical Gardens, and even garden centers.

Predators and Prey

Unfortunately, the brilliant coloring of koi fish makes them easy targets for creatures that wish to eat them. These range from wading birds like egrets, storks, and herons to small carnivores such as raccoons, foxes, and cats. This is why koi owners need to maintain a pond that is too deep for a wading bird to stand in. The fish’s habitat shouldn’t have overhangs, such as a low bridge, that a carnivore can use to reach in and grab a fish. It should also be shaded. This not only hides the fish from birds of prey and other predators but also protects the koi from sunburn.

Reproduction and Lifespan

Koi fish can enjoy an extraordinarily long lifespan. They can live for more than two centuries, but all started life as tiny eggs.

Koi breed in the spring. Males start following females around the pond, and when he catches up to her, he nudges her. This causes her to release her eggs, which can number in the thousands. He then fertilizes them. The eggs usually sink to the bottom of the pond, but they will stick to anything they land on.

Unfortunately, about a fifth of the eggs die or haven’t even been fertilized. The lucky ones hatch after about four or five days, but about a fifth of the baby fish die before they’re even an inch long. Some of them are even eaten by adults. At this point, breeders start culling the fish and save only the ones that look promising. The koi has a fast growth rate and might be ready to breed when it’s three to five years old.

Koi in Fishing and Cooking

Koi fish are treasured pets and are not fished, cooked, or eaten. Some live for so long that they are passed down as family heirlooms. However, the fish’s ancestor, the Amur carp, was raised for food. The fish started to be bred for ornamental purposes when genetic mutations caused some of the carp to develop patches of color on their scales.

Population

As an ornamental breed, the population of koi is most likely in the hundreds of thousands, if not more. It is now raised all over the world.

Types of Koi and Breeding

While all koi fish are the same species of carp, they have been bred to express certain distinct traits over the course of centuries. Because of this, there are 16 recognized groups of koi breeds, each with its own gorgeous patterns that set them apart, and dozens of variations of each of these primary categories.