Koi Fish Care In Aquariums

Last Updated on January 20, 2022 by Fabiola L.

Koi fish can make a beautiful addition to any home. If you plan on having them in your home, you will want to know proper koi fish care in aquariums. These gorgeous fish can make a great addition as a pet with the right experience.

Koi fish require a lot of work and need a proper set up in order to strive. They require someone with at least intermediate to advanced skills. However, owning koi fish can be very rewarding as they make wonderful and interesting pets.

About Koi Fish

Koi fish are native to Japan and are descendants of carp. These incredible fish can grow to be 36 inches long and live to be up to 50 years old. They are able to live in a variety of temperatures and conditions, making them popular pets.

Koi fish are able to form bonds with their owners, as they can recognize and take food from them. They are relatively calm, peaceful fish that can live with others. However, they do like to jump, so if they are in an aquarium they will need a lid.

Koi are hardy fish, which makes them great for having in garden ponds. However, they can live inside, as long as they have a big enough tank. They often do best in groups of five to 15 fish.

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Types Of Koi Fish

There are over 100 different types of koi fish that can be found worldwide. It is common for people to have a variety of koi kept together. Here are some of the most popular varieties that people have as pets.


Kohaku is one of the most popular kinds of koi fish. They come in a variety of red and white patterns. They were one of the first ornamental types established in Japan in the late 1800s.


Taisho Sanshoku

The Taisho Sanshoku koi was developed around 100 years ago in Japan. Also called the Taisho Sanke, their color patterns can be red, black or white.


The Tancho is one of the most beloved types of koi. They are white with a signature red circle, which resembles Japan’s flag.


Also known as the Hirenaga, Butterfly koi have beautiful fins. These graceful fins are symmetric and long-flowing.


Asagi’s are one of the most recognizable types of koi fish. They have a blue or indigo body with red at the base of their pectoral fins.


Bekko kois are only white and black in color. They display a simple stepping stone pattern.



Doitsu is a German variety of koi fish. They are unique as they either have scales along the lateral and dorsal lines or no scales at all.


Kikokuryu fish have a beautiful metallic appearance. These stunning shiny fish can come in different colors such as red, black, and white.

How To Care For Koi Fish

Many people choose to keep their koi fish in outdoor garden ponds. However, with the right care, you can have an indoor koi fish tank. If you keep them indoors, it is important to understand koi fish care in aquariums.

Koi fish can survive in cold and tropical climates, but their ideal temperature is between 65-75 degrees Fahrenheit. The pH level in their tank should be between 7-9.  They should not be kept in direct sunlight and proper water ventilation is vital, so they should have a high-volume filter.

Their tank should have a smooth, muddy or fine gravel substrate. They will tend to dig through the substrate, so live plants might not always work well in their enclosure.

They are known to accumulate a lot of waste, so be certain to regularly clean their tank. In addition, you will also want to do regular water changes to ensure the water is at a healthy level.

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Tank Size

A baby koi fish can be kept in a 30-gallon tank, however, they will quickly outgrow that. An adult koi fish will need at least a 250-gallon tank. If you have multiple fish you will want a tank that has plenty of room.

For every extra koi fish, you will want at least 50 gallons. For several koi fish, you may need an aquarium that is 1,000 gallons.

Some people will opt to keep their koi fish in an aquarium when they are juveniles. When they are adults, they then will transfer them to an outdoor koi pond. Having an outdoor koi pond is often more affordable and can even be easier to maintain than a large indoor tank.

If you are keeping your fish in a pond, you will want one that is ideally three feet deep, six feet wide, and eight feet long. Those who have more koi fish may opt for a bigger pond.


Koi fish are omnivores and will eat a variety of different foods. They eat food such as plants, algae, worms, seeds snails, and other insects. You can also feed them bloodworms, pellets, and freshwater shrimp.

Oftentimes, they will not eat other fish. They can be kept with other species such as goldfish, catfish, and Chinese Hi Fin Banded Shark.

Keeping Koi Fish Aquariums

Koi fish can make for wonderful tanks whether you keep them in a fish tank or outdoor pond. They do require a lot of care, but they can even learn to recognize their owners. In addition, they require a lot of commitment, as they can grow to be 36 inches long and live to be 50 years old.

There are over 100 species of koi, with many different varieties kept as pets. They come in lots of different color patterns, which are often white, black, or red. Typically, they are peaceful fish, but they are known to pick on smaller species.

If you plan to keep your koi in an aquarium, you will want one that is at least 250 gallons as they are big. If you are planning to have more than one, which is ideal, you will need at least 50 gallons for each extra fish. They do best in temperatures of 65-75 degrees Fahrenheit and need good water flow.

Do you have any questions regarding koi fish care in aquariums? If so, please ask any questions regarding koi fish and their care in the comment section down below.

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