How Long Do Koi Fish Live? A Complete Guide To Help Your Koi Live Longer

Koi fish are among the freshwater species that can be kept in aquariums. Yet, Koi ownership is a responsibility because you need to care about their lifespan.

Hence, how long do Koi fish live? Many factors influence their longevity, such as oxygen levels, pH level, water quality, food, wintering, genetics, and more.

If you want to get an ultimate answer, you can refer to this article. It will show you in-depth explanations of Koi’s lifespan. Let’s scroll down to learn more!

How Long Do Koi Fish Live? Overview Of Koi Fish LifeSpan

How long do Koi fish live in a tank? When kept in captivity in the best conditions, this carp species can live for 25 to 35 years.

Koi fish life expectancy depends on various aspects, so how long they live varies from one to one. Your Koi will live longer if you take good care of them.


Before learning about their longevity, you should get an overview of this fish.

The Koi fish is a type of carp. They live in freshwater ponds. Koi carp first appeared in China in the fourth century.

There are about 100 types of Koi nowadays, while many other varieties haven’t been identified.

Many people believe that a Koi’s popularity stems solely from its appearance, but it’s not entirely true. They are brilliant.

Like other carp species, these fish can recognize their owners as long as these people care for them regularly with the same person.

They can also remember their names and welcome their owner’s stroked behaviors. They are gentle and never show aggressiveness toward humans.

Life Cycle

If you want to enhance the lifespan of these carps, you should understand their life cycle if you have to care for them from fry to adult.

Spawning Season

This species doesn’t give birth to young offspring. Instead, these carps spawn, which is the process of laying eggs.

If a female is ready to start the reproductive process, she may begin to construct a nest-like structure, which attracts the male’s attention.

After mating, the female will lay eggs. The eggs will adhere to any surfaces they fall on after being released. The male will then fertilize the eggs.

After Spawning Season

Once spawning is complete, the parents must be removed from the pond. That’s because male fish may be hostile and cruel to their eggs, which is a problem. Furthermore, the female requires recovery.

Healthy eggs should be transparent, while infertile ones may be opaque or milky. Within one week after being fertilized, the eggs may hatch.

Fry Koi

The newly hatched Koi are often called fry. The fry won’t be able to swim right from the time of hatching so they will hide in safe places.

Adult Koi

These fish achieve sexual maturity between the ages of two and three years.

Factors Affecting How Long Koi Fish Survive

The typical lifespan of this species falls into three categories:

  • Koi raised in perfect settings, such as those with optimal water quality, nutritional health, pH levels, and little stress, can live into the 50s, 60s, or even 90s.
  • Koi raised by collectors have a higher chance of living longer than 25 years. Most Koi fish outlive their owners by perfect conditions and maintenance.
  • Koi fish bred by beginners have a substantially shorter lifespan, like 3 to 5 years. That’s because the keepers may lack the necessary hobby expertise.

This article will discuss the key points, including oxygen levels, pH levels, water quality, food, wintering, environment, genetics, and owner’s experience.

Oxygen Levels

The most common cause of Koi fish mortality is a shortage of oxygen. Algal blooms are a vital contributor to the reduction of oxygen in ponds.

During the day, algal photosynthesis produces oxygen. When algae in ponds grow out of control, they absorb more oxygen than they have, killing the fish.

The abrupt reduction of algae in ponds is another element that influences oxygen levels. Once algae disappear, oxygen levels drop, leading to Koi’s death.

pH Levels

Garden ponds having a pH range of 7.0 to 8.6 are ideal for these fish.

As a result, to balance the pH levels, it’s best to eliminate all decaying plants and residual fish food.

Water Quality

Water quality indeed affects Koi’s longevity. The water should not have chlorine, nitrates, nitrites, or ammonia.

If you keep them in low-quality water, your fish will get stressed and more prone to infections.


This species requires a nutritious diet for a longer lifespan, including protein, fats, carbohydrates, minerals, and vitamins.


Wintertime in Japan may be bitterly chilly. It indicates that carp may survive in severe climates with suitable pond winterization.

These carps hibernate in the cold months. Experts say that this action can benefit them.

If you want to see how Koi hibernate during wintertime, you can watch this video:


Japan is a world leader in this species breeding. Despite Koi breeders’ significant efforts to improve their genes, Japanese Koi live longer than domestic carp.

Owner’s Experience

Simply put, inexperienced fishkeepers will reduce the longevity of their carp to around 3 to 5 years.

They don’t have the expertise necessary to build and maintain a Koi fish-friendly environment.

On the other hand, an expert owner can provide perfect conditions for this species to live up to around 25 to 35 years.

How To Help Your Koi Live Longer? Perfect Tank Environment

These ornamental fishes are hardy in most environments. They do, however, require good maintenance if you expect them to have a longer lifespan.

To improve the lifespan of this species, follow these simple tips:

Set-Up And Tank Size

Koi fish are pretty active and swim all day and even night when seeking food.

The tank size will vary depending on the Koi type you keep. Below are some recommendations to consider:

  • A 30-50 gallon tank is suitable for juvenile Koi.
  • Mature Koi may require a tank with 200 gallons.
  • A tank with 1000 gallons of water and a depth of 72 inches is sufficient for a Koi group.

Keep your fish aquarium out of direct light and drafty areas.

Since these messy aquatic creatures will splash, ensure your aquarium is covered at all times.

When bringing new Koi to an aquarium, you should attempt to introduce no more than 2 – 3 once at a time, mainly if they are fully grown.

This species may be exceedingly messy. Even in well-organized tanks, the unexpected flood of new waste might cause bacterial disequilibrium.

Proper Filter

If you aim to create the healthiest habitat for your Koi fish, you’ll need a good filtration system. A pump will be necessary to operate the filters.

The most critical factor is that the filtration systems can filter all of your fish’s waste.

Due to the large amount of waste that big Koi produce, you will need to wash the filters more frequently.

To get the most excellent results, combining biological and mechanical filtration.

A biological filter contains millions of beneficial microorganisms that help lower nitrate and ammonia concentration in water.

On the other hand, a mechanical filter traps particles in the pond using foam or sponges.

Water Quality

The best gift you can give your fish is high-quality water to help them have a longer lifespan and live happily.

Regular testing will help you keep the quality of the water up. Water quality may be maintained by frequent testing.

Household water test equipment helps maintain the aquatic environment.


The temperature of your pond is crucial to the longevity of your carp.

Hot water is not suitable for them. Warm water has less oxygen and is more susceptible to bacterial growth.

Koi thrive at water temperatures from 65 to 75 0F and suffer in temperatures higher than that.

These fish can withstand the cold water if the pond has enough depth with a hole above the ice surface to allow carbon dioxide to exit and air to enter.

What is the ideal depth for a pond? If you reside in a harsh area, a pond around 3 feet is a decent rule of thumb.

This species goes into “torpor” mode in the wintertime. It is a brief hibernation period.

At this time, they will slow everything from their bodily function, breathing rate, or digestive process to conserve energy.

They may survive in the bottom section of the pond without having to consume during this period of hibernation.

pH Level

Maintain a steady pH level of 7 to 8 in your pond. Rapid pH fluctuations may be harmful to your fish and other species.

To keep the pond’s pH balanced, remove all rotting plants and remaining fish food. Filtration devices for water can help with this.

Furthermore, water additives prevent nitrates and ammonia from going into your pond, which might cause pH changes.


Maintain a daily lighting schedule for fish tanks, approximately 8 to 10 hours of sunlight every day.

Shaded spaces for your carp to retire to during the hot summer months are essential in outdoor ponds.


It’s unnecessary to feed your fish in the pond if the condition is excellent. However, they will tend to live longer lives if they eat high-quality food.

You should provide them with foods that are easy to digest and offer the vitamins and proteins they need to live a long and healthy life.

You should also pay attention to the frequency of feeding times. This species will require a more nutritious diet in hot months than in wintertime.

When the temperature is between 40 and 60 degrees, the feeding frequency should be once per day.

You may feed them about five times daily if the temperature is over 60 degrees.

Overfeeding the Koi can make them ill and allow ammonia to accumulate inside the water, so be careful.

Predator Control

These fish are colorful and lovely creatures who live in small, cramped places with little room to move around.

As a result, predators may immediately notice them while they have little chance of defending themselves.

Cats, possums, raccoons, or herons may find your pond tempting, causing your decorative fish to face death!

You must protect them from dangerous predators to get longer and happier life.

You can help your fish by installing motion-sensing barriers, providing fish caves, or covering the pond using protective netting.

Oldest Koi Fish On Record

Hanako, which lived for 226 years, was the world’s oldest Koi carp on record. It was a lovely scarlet-colored female Japanese Higoi.

In Japanese, the term “Hanako” means a flower girl. It was born in 1751 in Japan’s Tokugawa Era, in Horeki’s first year.

It was 226 years old when it passed away on July 7, 1977. Hanako was not just the longest-living carp but also the world’s oldest aquatic creature ever recorded.

No fish has surpassed this record up to now. Experts determined the actual age of Hanako by analyzing and studying its scales’ rings using a microscope.

Experts took Hanako from a pond in Mino Province’s deep highlands to determine her exact age.

They take off two scales from separate areas of its body using tweezers.

Professor Masayoshi Hiro of Nagoya Women’s University’s Laboratory of Animal Science methodically examined the distinct growth rings on its scales for two months.

The last Hanako owners were Dr. Komei Koshihara and Professor Hiro. They were surprised when Hanako’s age was revealed to be 215 years old at that moment.

The findings of a year-long investigation revealed that the rest of the carps in that pond were also more than 100 years old.

Dr. Komei Koshihara broadcasted about the age of Hanako to the entire Japanese country via Nippon Hoso Kyokai Radio Station on May 25, 1966. Hanako weighed 7.5 kilos and measured 70 cm at that time.

Nobody knows why she lived such an incredibly long life. Maybe it was the crystal-clean waters in the Japanese highlands and its owners’ great affection and care.

Koi Fish Care Guide – How To Pet Koi Fish

With the following suggestions, you may improve your carp care expertise and gain a better understanding of how to care for your fish:

Maintain Ideal Water Conditions

Koi carp are demanding, low-maintenance fish. If you keep them in low-quality water, they can develop a variety of health concerns.

The following are some common water quality issues that most carp keepers may encounter:

  • pH fluctuations
  • High Nitrite and Ammonia
  • Low-quality water
  • Overstocking

These are potential issues, but they are largely preventable and, at the very least, straightforward to resolve.

Inadequate water quality is responsible for more than 80% of Koi carp issues.

To avoid infections and other concerns, you must supply your fish with a healthy water environment.

What does it mean to have a healthy water environment? Suitable water parameters for healthy fish should include:

  • A pH of 7-8.5 is ideal.
  • Nitrate levels are between 20 and 60 ppm.
  • Nitrite and Ammonia levels are zero or negligible.
  • The minimum rate of oxygen should be 6 mg/liter.
  • There is no chlorine, lead, iron, copper, or zinc.

A clean-looking pond doesn’t mean it is an ideal living environment for your fish. They thrive in mineral-rich water.

This sort of water keeps pollutants from dissolving or causing severe harm to them. Harder water additionally aids in the prevention of pH changes, which may be highly harmful to your carp.

How can you make sure your fish have a healthy water environment? Here are some tips to consider:

  • Before you introduce these aquatic creatures, treat the pool with a dechlorinator.
  • Use a water pump to maintain good water circulation.
  • Install a filter to remove any toxins and waste.
  • Make sure the pond filter can clean the whole area.

Check The Water Often

Regularly checking the water quality aids in lowering the danger of illness in these aquatic creatures.

What should you do when checking the water in the pond? Follow some guides below:

  • To maintain your fish healthy, you should replace a minimum of 10 percent of the water monthly.
  • Purchase a water testing kit.
  • Fish might seem OK in low-quality water for a while. So, check the water quality every week to detect any problems early.

Maintain The Proper Water Temperature

These aquatic creatures are tough in the environment in the UK and may thrive in a freezing pond during cold months.

If the pond’s surface freezes, it will simply go into torpor mode until the surface thaws.

You may use a floating heater to create a hole in the ice surface to allow proper oxygen delivery.

These carp adjust their body temperature to the water temperature around them.

They require progressive adjustment to survive, which implies that you should not change the water temperature suddenly.

The air temperature fluctuates during the day or season, while the water temperature does not.

So, you will not need to be concerned about your Koi safety.

Select The Appropriate Filter

There are numerous fantastic pond filters available to assist you in maintaining healthy fish.

The challenge is to find one suitable for your pond’s condition.

You should consider your stocking level, pond capacity, and the development of Koi in the future when buying a filter.

Good filters may remove hazardous waste and trash from your pond while eliminating toxins like ammonia.

A good pond filter should provide your carp with clean, healthy, and pleasant surroundings.


aquarium filter

Pond filter

Apply The Proper Diet And Feeding Techniques

These carp eat both meat and vegetables. Quality fish food must provide vitamins, carbs, and proteins to enhance health, development, and color.

Feed them lettuce, peas, and tiny slices of melon instead of bread bits or goldfish flakes.

These aquatic creatures need less protein for the winter diet than in the summer months as their digestive system slows down at low temperatures.

Avoid Overcrowding

If you overcrowd your pond with Koi carp, they won’t have as much capacity to swim.

You should use 10 gallons of fresh water for each inch of carp with 1000 gallons as a minimum in a three-foot-deep pond.

Overcrowding koi pond


Ensure That Your Pond Equipment Is In Good Working Order

Pond equipment is essential to excellent Koi carp maintenance. If you invest in high-quality devices, you won’t have to pay more to fix problems.

Here is must-have equipment to ensure your fish have a healthy environment to live in:

  • System of high-quality filtration
  • Pond skimmer
  • UV clarifier
  • Aeration system
  • Powerful water pump

Popular Koi Fish Species

If you take up keeping Koi, it’s better to learn about some popular types to find the best way to raise them for a longer lifespan.


Asagi is an old Koi breed that provides the foundation for many succeeding varieties.

The front side of the fish has an elegant white and blue net pattern, with traces of red on its belly, tail, pectoral fin, and gill plates.

Asagi koi fish



Chagoi carps are more closely linked to Koi than other variations. Their color and size reflect Koi’s ancestors.

Muted, earthy tones varying from pale to muddy brown or dark copper colors are the most common hues in this species.

Chagoi koi fish



Kohaku, like Asagi, is among the earliest known and most famous Koi variations in the world.

These carp have crimson stripes that contrast with their white bodies.

Kohaku koi fish



This pattern is called Goromo in the United States, but Koromo in many other countries.

Every red scale that makes up their pattern is highlighted in blue, giving them a unique visual texture.

Goromo Koi fish



Goshiki has a complete white shell with blue and black scales coated with red markings.

They are the result of breeding between Sanke and white-and-blue Asagi.

Goshiki Koi fish



Kumonryu is an exceptional result created by crossing Matsukawabake and Shusui.

It has a scaleless shell with a white foundation and black stripes with blue dots.

Kumonryu Koi Fish


The Bottom Line

This article explains the concern of Koi owners: How long do Koi fish live? Their average lifespan is 25 to 35 years if you keep them in a good environment.

You can apply methods and tips to care for these ornamental fish to help them live longer and more happily. Hopefully, this post will be helpful for you.

Thank you for reading!