How to Raise Koi in Aquaponics?

Raising koi in aquaponics entails providing the fish with a particular environment that allows it to stay resilient and healthy. This situation is achieved by observing certain factors such as stocking density, pH range, water temperature, and proper diet. In this article, I will provide you with helpful information that you can utilize to raise koi for your aquaponics system successfully.

Why raise koi in aquaponics?

Koi aquaponics is both inexpensive to start and will save you money in the long run. It is pretty simple to add an aquaponics system to an existing pond, which many enthusiasts are interested in. Hobbyists will spend less money on water and primary koi feed, especially if they supplement some of the koi diets with their crops.

What are the different species of koi?

Approximately 100 different species of koi fish are available for your aquaponics, each with unique body forms, proportions, color variations, and scale patterns that set them apart. Below I shortlisted eight species of koi that I deem best for any aquaponics technique.


Kohaku is a red-patterned bright-white koi. There are two sorts of Kohaku: one is the most prevalent and has a red design all over it. Only a red mark in the center of the forehead characterizes the second form of Kohaku. Tancho Kohaku is an extra-special type, and due to its rarity, it is a highly prized specimen.


Utsurimono has a black base body with various colored patches, as the name suggests. Hi, Shiro, and Ki Utsuri are three gorgeous types of Utsurimono, with "Hi Koi" featuring a superb crimson base, Shiro; white, and Ki; yellow.


Koromo fish are beautiful koi that are easily recognized in a pond. Koromo, which means "clothing" or "robe" in Japanese, has a lovely Hi (red) pattern of Kohaku on their pure white skin and an indigo blue pattern on each scale of its Hi pattern.


Several varieties of koi are classified as kawarimono, including those that lack a distinguishing characteristic to be considered unique breeds of koi. Within the kawarimono category, there are a total of 14 distinct koi fish.

Hikari Muji

Hikarimuji koi fish are marked with a single color and shiny scales. The scales are well-known for reflecting light. This koi variation brings a burst of color and is ideal for people searching for a solid color to complement other multi-colored varieties. There are three various types of Hikarimuji: Ogon, Yamabuki, and Matsuba.


In 1910, an Asagi koi fish and a mirror koi carp were crossed to create the first shusui koi fish. A shusui koi with Asagi koi hues and scale lining on its back resulted from the koi breeding. The shusui koi's unusual koi scale patterns and contrasting rare koi hues made it an instant hit with koi fish hobbyists.


The Bekko is a non-metallic, solid-colored koi with black (sumi) patches on the body. White, red, and yellow Bekko koi are the three colors available. Shiro Bekko refers to the white variety. It's a pure white koi fish with black markings. The Aka Bekko, a red or orange koi with black spots, and the Ki Bekko, a yellow koi with black spots, are two different types of koi fish. The Ki Bekko (yellow) variant is the most uncommon.


One of the earliest breeds of gorgeous koi is the Asagi. Asagi Koi have different color patterns than the rest of their family. On the upper half of their bodies, they have bluish to light blue scales. However, the lower section, namely the belly, and mid-lateral area, is highlighted with vibrant red patterns.

Which species of koi is best for aquaponics?

The kohaku koi is a recommended species for aquaponics. One good reason is that its solid white body color with red markings is appealing to the eyes. Most importantly, the overall toughness of this fish explains why it is a popular choice.

What are the factors to consider in growing koi in aquaponics?

Stocking density

The overall health of your koi and the quality of the pond environment are directly influenced by stocking densities. Disease outbreaks are more likely in heavily stocked ponds. Heavily filled ponds add stress to the fish.

The higher the stocking density, the faster the contaminants must be removed, and the clean water must be reintroduced to the pond. Koi takes up more space, consume more oxygen, and add more ammonia to the system as they grow.

Water temperature

Koi fish can thrive in water that is between 34 to 90 degrees Fahrenheit, according to various shops that offer koi and koi supplies. Although koi may survive in extremely cold or hot water, they do not thrive in these conditions. This is particularly true if excessive temperatures last for a long time. When the water temperature is around 65 degrees Fahrenheit or slightly higher, koi thrive.

pH range

For koi, a slightly alkaline pH is excellent. The species requires a pH of 7.5 to thrive. A pH of 7 is neutral and will not hurt the fish, but a pH range of 7.5 to 8 is optimal. Anything with a pH below 7 is acidic and causes a lot of stress. An acidic environment necessitates quick treatment to return it to a neutral or alkaline state.

The technique of achieving the appropriate pH level in the pond is straightforward. Making small changes until the water reaches the ideal level is the key. Changes in pH should not be drastic because they stress the fish. A calm state of acclimatization is achieved by making slight, incremental modifications over several weeks.


Koi fish will eat anything they find edible that floats by in the wild, including algae, bugs, plant materials, and animal stuff. Koi can be fed practically anything that humans eat. Shrimp, fruit, veggies, and anything else not high in carbohydrates fall into this category. Bread and similar things are difficult for your fish to digest. You can also give them fish pellets to eat. Check to see if they're the proper size.

Here are the four food types that you can give to your koi fish:

  1. Spirulina algae
  2. Wheat germ
  3. Brine shrimp
  4. Fish food

Feeding koi fish high-carbohydrate foods are not recommended. You should also keep white bread, peas, and maize away from them. Carbohydrates are complex for koi fish to digest. Also, do not give them anything you've caught in the wild. Fish, beetles, frogs, and everything else fall into this category. They may be infected with parasites or diseases.

Fish tank

Koi are huge, slow-moving fish with a lengthy lifespan. In captivity, they can live up to thirty years and reach a length of almost three feet long.

As your fish mature, they will require more space to survive. The more fish you have, the more these space requirements get emphasized.

A tank or pond with a depth of at least ten feet and a capacity of more than 1000 gallons of water is ideal. Five or six mature koi will be able to thrive in this environment.

That being stated, it is not advisable to begin your system with fully grown, mature fish. Start with little fish instead.

This will allow your fish to become accustomed to the system while ensuring that your aquaponics system remains healthy and effective.

What are the pros and cons of raising koi in aquaponics?

If you weigh whether you should use koi for your aquaponics project, here are some advantages and disadvantages you should consider.


  1. Disease and parasite resistance: One good reason to breed koi inside your aquaponics fish tank is because of its resiliency against diseases and parasites. Unless, of course, you have neglected to provide the fish with an optimal growth environment, koi will rarely get sick.
  2. Tolerant of a wide range of water temperatures: Koi fish can endure a broad spectrum of water temperatures, 34 - 90°F (1 - 32°C), which is a good thing, especially if you are in a region where temperature fluctuation is normative.
  3. Aesthetically pleasing: Koi is a perfect choice to enhance the beauty of one's home or office.
  4. Long lifespan: As already disclosed in this post, koi fish can reach an age of 30 years. This feature is a plus because you will not need to buy new fish additions after a few months or years. Eventually, you save money because the koi you purchased years ago is still alive and making your aquaponics system well.


  1. Unedible fish: Basically, aquaponics is designed to help growers produce two types of nutritious foods: fish and vegetables. With koi fish occupying your fish tanks, you can only grow edible plants.
  2. Requires a large fish tank: For koi to reach its optimal growth, you would need to house it in a big fish tank. This fact could be an issue, mainly if you only have limited space for your aquaponics.

For decades, Japanese koi have been prized for their beauty and capacity to create tranquil environments in backyard living areas. As a result, many gardeners have turned to this colorful fish to help them bring the same value to their aquaponics systems. Even though they are inedible, koi are adaptable, bringing resilience and survival in various environments. This fish is indeed an excellent aquatic animal in your aquaponics setup. The details I provided above will help you be successful in raising aquaponics koi.

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