Koi Pond in Greenhouse

Koi Pond in Greenhouse: Can You Have a Koi Pond in Greenhouse

Are you wondering if you can have a koi pond in a greenhouse? There are several benefits to this decision, and also some not-so-great points. However, if you have set your mind to have a koi pond in greenhouse, this is the perfect article for you! Here, I am going to talk about how you and your fish can benefit from having a greenhouse over the pond and also the benefits a greenhouse get from Koi pond. In this article you can explore the various breeds of koi fish that you may never have known before. Let their beautiful patterns and colors enhance the visual of your yard and garden. Once you have passed the initial stage of building the pond foundation, the rest will be a piece of cake. Ready to know more about Koi Pond in Greenhouse? Dig in!

Koi Pond In Greenhouse 

Why Koi Fish Is Ideal For A Greenhouse Pond

The answer may really surprise you. I bet you will be planning to have your own greenhouse pond once you are done going through this section!

1. Koi Can Handle Cold Temperature

As beautiful as they are to look at, maintaining koi fish during both hot and cold weather is also not so difficult. Unless you are living in an extreme climate, your koi will be fine in their pond.

Koi Can Handle Cold Temperature

However, during extreme heat, you do not want your precious fish to boil in the water. For that reason, use a shade from the sun or take them away to an indoor tank or garage during that time of the year. The same goes for the winter months. Koi can handle a temperature of 12 degrees Celsius. Any lower than that, frozen ponds can kill your babies. So, move them to a better location for the time being if the temperature drops too low.

2. Protect Fish from Outside Predators and maintain temperature

Protect Fish from Outside Predators and maintain temperature

Another great benefit of having a greenhouse pond is that your koi fish will be safe from neighborhood kitties fishing for snacks. Other major threats can include raccoons, opossums, bears, foxes, otters, cranes, muskrats, crows, and hawks. The greenhouse may not look so appealing from the outside, but it will keep your fish safe. At the same time koi pond help to maintain the temperature inside the greenhouse. So its a pure win win in both ways.

3. Koi Fish Love Shades

Koi Fish Love Shades

 As discussed before, your koi can sustain a certain amount of heat during the summer months. When it gets too hot, your fish may suffer. So, create a shade for them with the greenhouse and let them swim in peace all day long.

4. Koi Fish Do Not Need a Deep Pond

Some koi fish ponds are as deep as 3 feet, and this is enough for koi fish to thrive. However, because these fish need plenty of room to swim around, do not overcrowd your pond with every variety of fish you can find!

5. Can Use Pond Water for Greenhouse Irrigation

Can Use Pond Water for Greenhouse Irrigation

The last advantage of a greenhouse pond is that you can use the pond water to irrigate plants and trees around it. Not only can you nurture your fish in the greenhouse, but also grow your own fruits and vegetables to sustain your life! Moreover, fish pond water work like a liquid fertilizer for greenhouse plants.

How Deep Should a Pond be for Koi

An adult koi fish measures about 15 inches. Keeping them in mind, a koi pond must hold over 1000 gallons of water. However, only 4 koi can accommodate that space. So, if you are planning to have more fish in the pond, prepare to fill it up with more water!The depth of the pond should be 3 to 4 feet in a warm climate. In a cold climate, you can dig your pond as deep as 21 feet! There is a reason behind that. In winter, water can freeze 18 inches to 24 inches deep. Therefore, if your pond is not deep enough, the cold will affect the fish. Moreover, a 4-feet deep pond must be 8 feet long. An 8-feet deep pond must have a surface area of 12 feet. On the other hand, a 21-feet deep koi pond needs a length of 17 feet.

How Deep Should a Pond be for Koi

Furthermore, if your koi pond has a sloped edge, you can use a 2:1 or 3:1 slope. The slope falls 2 to 3 feet for every 1 feet depth. Having vegetation around the pond will prevent soil erosion. Plus, since there is less oxygen in the depths of the pond, place an aerator to supply more air to the fish.

How Many Koi Fish Can You Have in a Pond

Koi fish grow extremely quickly and become quite large at some point in their lives. A mature koi fish needs at least 50 gallons of water to thrive in the pond, whereas a small koi is alright with 29 gallons. The last thing you want is to overcrowd the pond with koi, and make their lives miserable in there! So, ideally, a 1500 gallon pond should hold about a dozen of adult koi fish. An adult koi fish can measure upto 15 inches, and that is what you should keep in mind.

Here is an average estimate of how many koi you can have in your pond.

Pond Water Volume Number of Koi Fish
250 gallons 1 to 2 koi
300 gallons 1 to 2 koi
500 gallons 2 to 4 koi
750 gallons 3 to 5 koi
1000 gallons 4 to 6 koi
1500 gallons 6 to 10 koi
2000 gallons 8 to 12 koi

Benefits of a Greenhouse Pond

Benefits of a Greenhouse Pond

Building a greenhouse for your koi fish pond may sound outrageous, but some people have reaped the benefits of this. Though maintaining a pond inside greenhouse is a difficult task but it’s also have some advantages.

Provide irrigation support for greenhouse plants

Gardeners can use the greenhouse’s old pond water  for irrigation purpose. Because fish pond water not only the source of water supply for plants but also works as a liquid fertilizer for some plants. If there is any air plant inside greenhouse then those fish pond water can be also use for airplant care and growth and its also work as an excellent fertilizer for them

Hold the moisture for greenhouse soil

Hold the moisture for greenhouse soil

Pond inside a greenhouse can hold the soil moisture level during the time of hot summer. So the soil of greenhouse does not get too dry in hot season.

Control the humidity level inside the greenhouse

Pond water evaporates during the time of hot summer and maintains the required humidity level inside the greenhouse. So we can say it’s an alternative of plant humidifier .

Things to Check before Make a Greenhouse Pond for Koi Fish

Already decided to get a greenhouse pond for your koi fish? Read the details below to get started with the project!

Fully Insulated Structure

Full insulation is important for the colder months. So, make sure that both the walls and floors of the koi pond are totally insulated. This will reduce heat loss and keep the fish happy.

‘Off the Shelf’ Greenhouse

To protect your fish from predators, bad weather, and other pollutants in the environment, get an off-the-shelf greenhouse. The greenhouse will keep the fish warm in winter and cool in summer.

Modern and Efficient Filtration

Be mindful of the filtration system that will be put in place. It must be efficient, able to provide excellent water quality at all times.

Low Wattage Pumps

The pumps for the pond must use low watts since it is going to be running most of the time. You want to save as much energy and money as possible. Because owning and maintaining a greenhouse koi pond is not cheap!

Sufficient Amount of Water

You must have a sufficient amount of water in the pond to let the koi swim in peace and grow up healthy. For example, have 3000 to 4000 gallons of water for a pond that measures 20 x 12 feet.

Types of Koi Fish

Types of Koi Fish

Koi fish can be classified based on their patterns, colors, and history. Let us have a look at some of the most common varieties of koi genealogy that exist today.


The Asagi koi is distinguished by its blue body and red at the foot of its pectoral fins. This red color is known in Japanese as ‘Motoaka’.


The Bekko koi can be identified with black spots on its white body. They are bred from the Taisho Sanke koi.


Doitsu koi is a German carp with no scales on its body. However, you may notice some scales on some of them.


The Ginrin koi can be identified because its body is full of diamond scales. Their scales shine in the light and make them look majestic!


Goshiki koi can have a variety of colors. They were bred from Asagi and Kohaki koi in 1918. You will find them in shades of blue, grey, and black enmeshed over their sleek bodies.


Hirenaga looks like a butterfly because of its beautiful, flowing fins. The fins are usually identical and symmetrical.

Frequently Asked Questions

Should a Koi Pond be in the Sun or the Shade?

Koi ponds are known to stay better in the sun than in the shade. However, having it in the shade will prevent algae from overgrowing in and around the pond.If the sun is too hot, it can increase the heat capacity of the water during the summer season. So, having a shade will be nice and comfy for the little fishes.Other than that factor, the koi fish love to bask in the sun during the day. The sun also helps aquatic plants thrive at the same time. Fun fact: koi get their vitamin D indirectly from the sun, so yes, give them some sun from time to time.

Can You Have a Koi Pond Indoors?

Who would not want to have a koi pond inside their homes or offices? But you need to have enough space for the pond to be located indoors. If your indoor pond ends up being smaller than a regular outdoor pond, make sure to not let too many fishes swim in it. According to experts, mature koi do better in outdoor ponds, whereas younger koi can be kept indoors. The outdoor pond requires about 50 gallons of water per older fish, and the indoor one needs about 29 gallons per younger fish. Another thing that needs mentioning is that if you do not have a proper pond management system in place, the indoor pond will smell. On top of that, the turbid water will make your interior space look ugly.

Can Koi Survive the winter in a Pond?

Koi fish can survive a cold temperature as low as 0 degrees Celsius. Just make sure that the water is not freezing into solids. Then, that may be difficult for the fish to sustain. The fish also need enough oxygen and water to make it through the winter months. But there are certain things you can do to keep them alive during that time of the year. Do not feed them when the temperature is 50 degrees Fahrenheit. You can also move them to a tank or garage space for the time being. Another great option is to build a greenhouse over the pond. You can also implement solar cover for pools. Furthermore, move the aerator close to the surface.

What is the Best Temperature for a Koi Pond?

Your koi pond needs to be at least three feet deep, or else the water will freeze into solids during the colder months. Indoor koi fish prefer cool water that is between 18 to 24 degrees Celsius (65 to 75 degrees Fahrenheit). Do not put them in water that is below 12 degrees Celsius. But their ideal temperature is 18 to 25 degrees Celsius.


If you have decided to do some research on koi pond in greenhouse, then you have already taken the first step. The building process may be a challenge accompanied by a few trials and errors on the way. But you will be able to enjoy the fruits of your labor at the right time. Though the cost has not been mentioned anywhere, you may need around $9000 to create a koi pond greenhouse from scratch. If you already have a pond, then the cost will be reduced significantly. Hope this Koi Pond in Greenhouse article help to build your own greenhouse pond

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