Koi Hanako was the oldest koi fish ever recorded at 226 years old. In Japan, Koi Hanako was a stunning scarlet-colored female Higoi. Her given name, Hanako, translates to “flower girl” in Japanese. 

Hanako was born in the first year of Horeki, in the middle of Japan’s Tokugawa Era, in 1751. Hanako died on July 7, 1977, at the age of 226. Hanako is now not just the oldest Koi but also the longest-living freshwater fish on record. To this day, this record has not been broken.

If you’re a rookie Koi keeper looking to acquire Koi for your garden pond because they have a life expectancy of 100 years, you could be in for a surprise!

Unlike popular assumptions, the life expectancy of Koi fish varies from keeper to keeper. As a result, there is no single response to the question, “How long do Koi live?” Let me clarify.

So, what is the Average Lifespan Of Koi Fish

Koi fish are known to live for a very long time. Their longevity, however, can vary greatly depending on the fish’s habitat and genetics. The common carp’s life expectancy is 30 to 40 years in the wild.

The average koi lifetime in captivity is 25 – 35 years. Therefore, it is extremely typical in Japan to come across a koi over a century old. This is one of the reasons why koi fish have developed such a following in Japan and throughout the world.

Which Koi Fish species live the longest?

The majority of Koi fish species have a rather lengthy lifespan. On the other hand, the Japanese species tend to live the longest, primarily if they’re being maintained in captivity by Japanese fish breeders.

The Kohaku, a white koi fish with red spots on its body that may live for more than 50 years, is one of the most popular koi fish.

The Taisho Sanke is another well-known species, having a white base color with red and black spots all over their bodies.

Why do Koi fish live for such a long time? Consider the following factors:

A koi fish’s lifespan is determined by various factors, including its genetics, the amount of experience of its owner, and the circumstances of its confinement habitat.

Domestic koi fish have an average lifetime of 15 years and are koi variations typically found in western aquariums. However, Japanese koi fish, cultivated from ancient Japanese gene pools, may live for 40 years on average, with some lasting well into their 60s.

Novice fishkeepers will unwittingly reduce their koi fish’s lifetime to about 3-5 years simply because they lack the expertise necessary to build and preserve an environment that allows a koi fish to live longer.

An expert koi owner can provide optimum conditions for a koi fish to live an average of 25-35 years. In this situation, introducing a koi youngster into your aquarium will almost certainly result in a lifelong companion.

Clean water and a good pond filter, excellent koi food, and lengthy harsh winters are all environmental variables that contribute to a long lifetime. As a result, the Koi’s metabolism will be significantly slowed during the winter season. During this time, the fish may consume very little food. Therefore, it is advised to halt feeding altogether during the harshest winter months.

Genetic factors also influence a koi’s potential lifetime. These decorative carp are known as Nishikigoi in Japan. They are bred for specific characteristics such as body form and color.

Of course, being huge is beneficial, but only if the body form and colors are preserved. Therefore, Koi are frequently cultivated for various features outside of Japan. The popular butterfly koi, for example, are developed to be considerably tougher and grow much quicker. As a result, a koi fish that lives for over 200 years, such as Hanako, is exceptionally unusual.

So, why do Japanese koi fish outlive other species?

  1. Knowledge of koi-raising in Japanese culture. Western fishkeepers have far less expertise in cultivating traditional Japanese koi types. Meanwhile, Japanese culture has an advantage in growing Koi, with expertise passed down via generations of koi fishkeepers. For one reason, western koi breeders are obsessed with producing fast-growing koi fish variations, which has resulted in a dramatic reduction in the average lifetime of domestic koi types.
  2. Koi genes from ancient Japan. Because Japanese rice farmers were the initial breeders of current Japanese ornamental carp types, they had the opportunity to hand-pick only the best koi specimens, ensuring that the koi gene pool remained diversified and pristine. As a result, even when koi fishkeeping became popular in the Western world, the best Japanese Koi never left their motherland.
  3. Japanese Koi hibernate. The life cycle of a Japanese koi fish is known to include periodic phases of hibernation throughout the severe and cold Japanese winters. Living in a cooler climate and reducing their metabolism for many months each year is one of the most significant elements influencing the Japanese Koi’s extended lifetime.

How Do You Determine the Age of a Koi Fish?

In captivity, determining the age of a koi is simple: ask the owner. However, a bit more inquiry is required in the wild or public koi ponds.

A koi fish’s age may be determined by counting the rings on its scales under a microscope, just as we can age trees by counting the rings on their trunk. Each ring on the Koi’s scales generally indicates at least one year of life. Another way is to measure the Koi’s ear bone size, which is significantly more intrusive.

Contrary to common perception, the size of a koi cannot be used to determine its age.

Do Koi pass away from old age?

Koi, like all living things, are subject to age and death. However, because koi fish have such a lengthy existence, relatively few of them ever die of old age. Instead, most koi fish die due to a lack of oxygen and nourishment, environmental changes, illness, or being chased by predators.

How can I ensure that my Koi live a long and healthy life?

Step 1: Ensure proper filtration and water quality.

As we have repeatedly stated, water quality is the most critical factor influencing fish health.

Step 2: Refrain from overstocking your pond.

We understand that Koi are extremely little when they are young. It’s difficult to imagine the lovely 4-6″ fish turning into a >24″ monster. But they have the potential to grow to that size. It is advised that each Koi have 250 gallons of water to call their own, with pregnant females needing 500 gallons.

The majority of koi owners will overestimate their water-to-fish ratio. We know this to be true. If you can build a larger pond, that’s fantastic, but it’s unlikely. And we’re not advocating you kill off a particular percentage of your fish; be conscious that you’re overstocked and will most likely face a filtration or space crunch in the future.

Step 3: Stop purchasing new fish.

New fish are the second leading source of disease in koi ponds, trailing only poor water quality. Unfortunately, most koi owners are not prepared for a proper quarantine, and the protocols of pet or koi retailers vary greatly.

Most of our koi owners are looking for the “ideal” fish to round out their collection. We strongly advise you to resist the desire. It reduces the amount of time your filtration has to function, the amount of room your fish has, and the possibility of disease entering your pond.

Step 4: Maintain your home with care.

Remember the most common cause of mortality in older fish? Someone forgets to turn off the hose. When I worked at the aquarium, it was assumed that everyone would overflow some system at some point during their employment. Fortunately, mine occurred in our quarantine area, where no one was present, and the floor drains cleaned it up.

I took my hair down and wrapped the rubber band around my wrist every time I filled a tank after that. It’s difficult to ignore that reminder when you’re filthy and sweaty and despise things around your wrist.

Choose something that works for you and stick to it, no matter how many times you think to yourself, “Oh, I won’t forget I’m filling the pond.” Set a reminder on your phone, read a book while you look after your filling, or use an irritating cue, such as a tight rubber band around your finger or wrist.

Step 5: Visit your aquatic veterinarian regularly.

Preventative medication is essential for the longevity of any animal, including yourself. So why do you believe your doctor advises a yearly physical and cancer screenings? Because catching something early raises the odds of successful treatment. By giving your fish a yearly or biannual checkup, your veterinarian can detect and treat health issues, including cancer, earlier.

Is there a cost? Without a doubt! As with any other aspect of healthcare, you get what you pay for. Your neighbor who attended a weekend koi course and offered to evaluate your fish for free will never be able to provide you with the results of a trained, experienced aquatic veterinarian. We do exist.

Can they use ultrasound to scan your fish for cancer? We can do it. If you cannot locate someone in your area, your local veterinarian of any specialty will be able to consult with us. In addition, we would be delighted to teach any veterinarian how to see fish.

If you follow these procedures, your Koi will be well prepared for a long, healthy, and happy existence!


Koi fish generally live for roughly a half-century. However, when kept with an inept fish handler, they survive for a shorter time. On the other hand, they can survive for two to three decades if kept with expert fish handlers.

When koi fish are left alone in their native habitats, they live the longest. However, this lessens when they are housed alongside fish handlers in man-made habitats.