Koi Fish Lifespan

Amazing Koi Fish Lifespan | We don’t get to live that long

Have you been wondering how long Koi fish lifespan is? Well, get ready for some amazing facts.

In this article, we will provide you with the nitty-gritty facts about its lifespan, which affects its lifespan and how you can work to achieve a similar lifespan in your tank.


Hanako who died on 7th July 1977 at the reported age of 226 years is the oldest recorded freshwater fish known.

She was a female Koi and her Japanese name “Hanako” translates to “flower girl” in English. She was passed down through several owners, the last one being Dr. Komei Koshihara of Higashi-Shirakawa Village, Japan.

The average Koi fish lifespan in Japan is about 25 to 35 years and about 15 years for Koi found outside of Japan. From extensive research, it has been noted that their lifespan is affected by several major factors. Here are some of them.


Koi Fish bred in japan have been found to generally live longer. This has been tracked down to the weather being favorable for the Koi. During the Japanese winter, they can hibernate which ideally keeps their weight in check.


The quality of food does play a significant part in Koi’s lifespan. Feeding Koi unhealthy foods lead to their early deaths from complications resulting from non-nutrient-rich foods.

It is important to ensure that you only purchase your pet food from reputable sources. Some people prefer to make their fish food in this way, they can tell exactly what they are feeding their fish.


In the West, there are numerous breeds of Koi which have been bred to grow faster due to pressure to meet market demands. This has continuously led to the decline of the Koi fish’s lifespan.

Most of the Koi fish in japan have been bred by families for years, with the now-famous Japanese commitment to duty and perfection, with minimal experimental crossbreeding. This has enabled them to maintain high-quality breeds.

koi fish lifespan

How do I increase my Koi fish lifespan?

Koi have been able to live a long and healthy life over the years. So you won’t need to be worried about elongating its lifespan. All you will be required to do is maintain a healthy pond for their existence. This way, you can ensure that nothing shortens its lifespan.

Ensure ideal conditions for your Koi fish and you will be surprised that they outlive most humans. Here are some tips on how to ensure this.

Clean Quality Water

Always work to ensure decaying material is out of your pond. This is because decaying matter can lead to the production of harmful gases. You can achieve this by doing a couple of cleanings regularly over a year.

Regular Water Changes

Ensure you cycle your water regularly. This will check on the levels of chlorine in your water. You can use sodium thiosulfate to dechlorinate the water.

Reduce the chances of accidents in your pond by not topping off the pond with a hose. Instead, use a timer at the end of the hose.

See also: Fish that jump out of the water in Florida

Check on your water pH parameters

You need to ensure your water pH ranges between 6.5 to 8.4. The perfect pH level is about 7.4. However, regardless of the value, you need to ensure that the values are stable.

Also, it is important to note that pH levels change during the day. The levels are lowest just an hour before dawn and highest at midday around 2 pm. This is because algae change these levels during photosynthesis.

Oxygen Supply

During the night, oxygen levels in the pond drop by about 10 points. Without supplemented air being driven into the pond, Koi fish may end up being stressed.

They may have to shift to upper surfaces of the pond for more air making them vulnerable to predation. This is why aeration is vital.

See also: How do you treat Popeye in betta fish?


Temperature fluctuations are seen during the cold nights and warm daytime. This also varies from season to season. This is why during the cold winters; you need a heater to keep the water warm.

Likewise, during the summer, you need shade to protect your fish from extreme heat. But not so cold to inhibit algae from growing.

Water Volume

The more the water volume and depth in your pond, the better it is for your Koi. This is because small volumes and shallow waters allow water parameters to fluctuate greatly between values.

As we have seen earlier; stability of the water is important for Koi. Also, Koi fish grow quite large as they max out on their lifespans. Therefore, it is advisable to allow around 800 gallons or more per 1 Koi fish.

Food Quality

Use quality food for your Koi. Avoid cheap and non-nutritious foods. Koi fish may develop a fatty liver tumor if on poor nutrition. Do you want that to happen to you Koi?

See also: Is salmon high in mercury

Breeding | How do I determine the sex of my Koi?

There are several reasons to want to know the sex of your Koi. This is important to know during breeding. Some Koi lovers are just curious or may want to give their Koi the right gender names.

It is convenient to know the sex of your Koi when they are about 12 inches long and mature. This does not mean it can’t be done before then. With some accuracy, this is achievable. It’s pretty simple but not obvious to determine the sex of your Koi.

There are two major indicators of sex in Koi; the easiest being studying the fin shape and color. Male Koi possess smaller and more pointed fins that are full of color and opaqueness. Female Koi have larger and more rounded fins that are translucent and to the extreme even transparent.

The second indicator, which is slightly tougher to note especially in younger Koi but still works, is their body shapes. Male Koi tend to be longer and slimmer while the females are rounder to allow for the accommodation of eggs. Generally, female Koi grow larger than males.

Great Koi Tank Mates

Before putting another fish with the Koi fish, there are several things you need to fast consider. Here are some;

  • Ensure that the species of fish is not aggressive. Keep social fish with your Koi to prevent unnecessary attacks on your Koi fish. You want to ensure a happily ever after in your tank.
  • Keep fish of similar size to the Koi
  • Select a fish that doesn’t require too much care. You don’t want to be overwhelmed by taking care of two fish.
  • The selected fish should not engage with the koi in food fights.
  • A bottom feeder will be highly favorable.

Some great ideas would be Barbel, Barbs, Catfish, Goldfish, Golden Orfe, Tench, Pleco, and Sturgeon.

See also: Does farmed fish have lower mercury?

How big do Koi fish grow and how long does it take?

Most Koi fish end up being 24-26 inches long. During the first 18 months, Koi may end up being stunted. However, you won’t have to worry about this if you purchased your Koi from a reputable source. A good number of Koi grow about 4-6 inches each year.

This growth slows down during the winter season enabling them to get larger by mass. To max out your Koi’s growth, you will either need a small population in a large pond or have regular water changes.

Water changes of about 10% a week and a complete water change twice a year is a great way to handle this.

Females tend to be slightly bigger than their male counterparts reaching 26-28 inches long for a quality Koi fish.

FAQs: More Interesting Facts About Koi

What is the biggest koi fish on record?

The biggest Koi on record was named Big Girl. She weighed a staggering 40 Kilograms with a length of 4ft. The fish was bought from a Japanese Breeder by a British breeder Geoff Lawton. She is a kagoi breed carp.

What is the most expensive koi ever sold?

The world’s most expensive Koi sold for 1.7 Million $. It took first place grand champion at the All Japan Koi Show of 2017.

Why are some people willing to pay so much for some koi fish?

Breeding top-quality Koi can be a capital-intensive and time-consuming task and this translates directly to the end-product cost. The quality of baby koi fish is also heavily reliant on the quality of the parent fish and this calls for higher investments by the breeder.

Breeders who buy top-quality Koi can recoup their investment and make a tidy profit by breeding the fish and also having them participate in shows and tournaments where they earn some good money from entrance fees and prize money.

Can you eat koi fish?

Yes. It is perfectly alright to eat Koi fish. But it is good to do a background check on the source of the fish you will be eating.

Koi are quite expensive due to the effort that goes into taking care of them. Due to this factor, some Koi, especially those bred on commercial ponds, have occasionally been related to the consumption of chemicals and food that may be bad for your health.

Where can I get Koi fish for sale near me?

This question keeps popping up but it does not have a straight answer; it will solely depend on your location.

While trawling the internet is one option for looking for buyers, I would recommend that you look for a reputable local supplier.

This is ideal as you can also go through previous buyers’ reviews and also compare prices from different vendors before ordering.

You don’t need to worry about the lifespan of your Koi as it will probably live longer than you. Just ensure you maintain a suitable environment for your Koi fish.

In their 50’s, Koi fish’s immune system begins weakening. This is where these factors are to be followed to the latter.



Southern Regional Aquaculture Center (SRAC): Species Profile: Koi and Goldfish