April 21

What is a Koi Pond and How to Build One


Everyone loves a koi pond in their backyard to house the beautiful koi fishes and also keep homeowners engaged and entertained. It is such a thing that will not only keep you happy but also will prove to be of some help to the ecosystem as well.

What is a Koi Pond?

koi pond construction

If you have ever wondered what a fish tank without its glass walls would look like, then koi pond is bound to be your answer. It is a pond, made artificially, for koi fish exclusively. The pond is usually 4’ deep. However, in some cases, it can also be 5’-6’ deep.

Sounds extravagant, does it not? Well, to be honest, it is. However, you could rest assured that it would be worth every penny that you spend.

Sometimes referred to as the “Swimming pool for koi,” these ponds might look deceptively simple, but in reality, a lot of hard work goes into the building as well as maintaining them. Once done, they are absolutely stunning to look at.

Here you might ask the question if a koi pond is a part of the landscape and whether building one would require a good deal of planning. To answer the latter question first, a lot of intricate planning goes into building a koi pond because we need to understand this, they are permanent and any fault in their planning could prove detrimental to your living conditions.

Now coming to the former question, whether or not koi ponds are a part of the landscape, the answer is no. It is not a landscape feature. However, it is a feature in the landscape. It is much like a swimming pool. In fact, it is a swimming pool for koi fish.

Here one might also ask another vital question and that is, whether koi ponds are exclusively for koi fish or whether other fishes as well could live in them. The answer is yes. Other fishes can live in it as well. They are not something highly exclusive. In fact, the greatest advantage and joy of a koi pond is the fact that it somewhat becomes a natural habitat for a wide range of aquatic life, and thus, every penny you spend in building and maintaining, it becomes completely worth it.

While fishes like goldfish can easily survive in it, not all species will be able to do the same. And, in a koi pond, there is no compromising on the health of your fish. So, before introducing a new species of fish in the pond, it is absolutely essential and crucial that thorough research is conducted so that your koi pond can remain to be absolutely healthy.

Apart from money and some extensive and intricate planning, all a koi pond needs are space – lots and lots of it. If all the requirements are met, you are in for an absolute treat. It may have been artificially built, but once completed and running, the pond easily gets converted into a phenomenal natural habitat for a wide variety of aquatic life. It is simply breathtaking and absolutely beautiful. In certain exceptional cases, a koi pond may also have a waterfall in it. It looks stunning.

However, it is also to be kept in mind that it is not a part of the filtration system. Also, to maintain an unobstructed and clear view of the koi pond, external aeration technology is absolutely vital.

How to Make Your Own Koi Pond in the Backyard?

Building a koi pond is truly a gargantuan task. It not only requires a lot of time but also involves a lot of planning, a lot of investment, and also a lot of maintenance. A koi pond is not just a thing of beauty, but it keeps you happy and calm as well. It is simply wonderful to look at and it will keep you both entertained and engaged at all times.

Now you might be wondering as to what are the things that you could possibly require when you want to start building your very own koi pond in the backyard and how to go about with it. This section lists out all the things, both technical and non-technical, that you will need while building your own koi pond. It also contains a step-by-step guide that will also help you build it.


  • Bacteria tank
  • Water filtration system
  • Protein skimmer
  • Artificial aeration system
  • Liner
  • Water pump
  • Rocks to put on the bed of the pond
  • Plants for the bed of the pond
  • Freshwater
  • Koi fish

Apart from these, there are a number of non-technical requirements as well. They are as follows:

  • Proper and intricate planning
  • Space – lots of it
  • The proper research regarding the fish to be kept in the pond
  • Commitment

Although the list of all non-technical elements required for the making of a koi pond may appear to be funny, they are to be taken very seriously in order to build a koi pond very successfully. Let us now look at the steps of building the koi pond.

 Step by Step Guide

  • Location: The first and foremost thing that should be considered by the builder is the location of the pond. The backyard is fine but what you really need to ensure is that there is enough space out there, because let us face it, a koi pond requires a lot of space.
    The added advantage of having the koi pond in your backyard is that you will be able to enjoy it to your fullest, and also, you would be able to take proper care of the pond as well as the fishes. Make sure that the spot you select is neither too warm nor too cold. It would help in preventing frequent temperature fluctuations and would help the koi fish to survive in more optimal situations, and it would ensure that they have proper health.
  • Size: The next thing that you need to consider while building your koi pond is that how big you really want it to be. If need be, feel free to mark the ground because, honestly, it helps a lot. This is the step where people commit mistakes most frequently. You should be all the more careful if this is the very first koi pond that you have ever built.

koi pond depth

    People tend to build a pond that is too small for usage. The smallest that you can build would be 1500 gallons. Yes, you read it right. It sure does sound huge. But, in reality, experienced koi pond owners would say that a pond lesser than 1500 gallons is simply no good because it is too small. Remember that this is an aquarium without those glass boundaries. So, make sure that you make them large enough.

    • Budget: The next step is, by far, one of the most serious ones. If you are wondering what it is, then let us break the suspense here. It is the budget for building the koi pond. Let us face it. Building a koi pond might sound pretty simple, but the costs of doing the same can be really heavy.
      As per the most recent records, building a koi pond of your own might cost you anything between $500 to $15,000. Shocked at the price range? Let us elaborate a little here. The most basic type of DIY koi pond costs between $500- $1000. The cost tends to increase with a steep slope once you decide to install more and more equipment in it. The more lavish your pond, the more is the cost of building it. But, there is absolutely no reason for you to fret because the end result would be very beautiful and pleasing.
    • As has been said earlier, a koi pond is not essentially exclusively built for koi fish. You could also keep other suitable species of fish in it. Before you start building your pond, make sure that you have completed all the necessary research work because once the pond is built, you would want to get it up and running as soon as possible.
      Make sure that you take into consideration the food habits, the temperature requirements as well as maintenance requirements and procedures. All of these are of prime importance to ensure that the koi pond is absolutely beautiful and healthy.
    • After all the non-technical stuff is done away with, it is necessary, to begin with all the technical stuff. The first thing to be done here is to evacuate the spot that you have selected to build your koi pond in.
      Considering that it is a pretty big job and also that it requires some advanced equipment, it is recommended that you get in touch with a contractor to do this work for you. Even if you are building the smallest koi pond possible, still there is a lot of work to do. Once done with this step, you could safely move on to the next.
    • Dimensions: After the spot has been evacuated, it is necessary that a hole of proper dimensions be dug for the pond. It is essential to remember that a koi pond is a minimum of 4’ deep. In some cases, it could also be 5’-6’ or even deeper if required. It must also be kept in mind that the minimum capacity of the pond is 1500 gallons. Make sure that the pond is dug, keeping all these things in mind. A contractor charges about $21 to $42 for every square yard of ground that needs to be dug.
    • A bacteria tank is also very essential for your koi pond. The koi fish produce a very special type of bacteria that helps in regulating the conditions inside the pond for them. This bacterial tank, once installed, will help this special bacteria to thrive in the pond, and this would, in turn, help in regulating the water in your koi pond favorably for the koi fish to be able to survive in it properly.
    • It is recommended that you also build a waterfall in your koi pond. It helps in the proper water circulation in the pond. You could use the mud from digging the hole for the pond to build the required waterfall.
    • Seal the pond: Once that is done, you would need to seal the pond with the appropriate liners to ensure that the water does not leak or seep through the pond. These liners are available in three varieties, namely, fiberglass, rubber, and cement. You could choose whatever you like. This step needs to be carried out with absolute precision to ensure that no amount of water may leak out of your favorite koi pond. The variant that you choose would reflect the cost of building your pond. It is crucial to seal your koi pond properly.
    • A water pump is to be installed next. All the water bodies, that is, the koi pond and the waterfall as well, need some sort of a water circulating system so that they can keep running smoothly.
      When choosing a water pump for your koi pond, make sure that you select one in accordance with the size of the pond. Too small a pump for a certain pond would simply be useless, and it would be a bad investment. So, before getting your water pump, make sure that you research thoroughly.
    • Water filters come next. These are absolutely necessary for the proper functioning of the pond. It is something that cannot be done away with. These water filters serve a two-fold purpose.
      Firstly, it converts the ammonia produced by the fish into harmless nitrates. Secondly, it helps in removing the fish waste from the pond. This ensures that the pond is absolutely clean and the visibility is absolutely perfect. It also ensures that the fish living in the koi pond has a proper environment to live in. Select the water filter very wisely since it is very crucial to the health of the pond.
      With these, you could also install the aeration system as well as the protein skimmers to obtain the best possible results. The aeration system ensures that there is proper circulation of oxygen in and out of the pond so that the fish can breathe properly in it. Installing it also ensures that with proper air circulation, clear visibility of the pond is maintained.
    • The next step is to add rocks and plants in the pond as much as required. The rocks can be bright, beautiful, and decorative. However, just make sure that they are absolutely safe for the fish in the pond. Also, try to add natural vegetation to the pond. It is the best.
    • The second last step in the procedure is to fill the pond hole with fresh water. This step could also be done before adding the plants to the pond if required.
    • The final step is to add the koi fish to the pond. However, it must be mentioned here that you should wait for the correct time to drop in the fish in the pond. The pond must achieve proper water circulation before the fish is added to it.

    Koi Pond Maintenance Guide 

    Just building a koi pond is not enough; maintaining it is a big deal as well. A koi pond requires a great deal of maintenance. If you are wondering how you would maintain your backyard koi pond, don’t worry because this section is here to help you out in all possible ways. You must remember, first and foremost, that a koi pond requires regular, extensive maintenance and it might look a wee bit complicated too. The following are the steps you must follow:

    • The quality of the water is of prime importance. Although koi fish is known to be the hardiest of all fishes, the drop in the water quality can be detrimental to their health. Performing regular water checks are very important to ensure the same. Although koi fish can survive in a wide range of conditions, it is best to provide them with optimum living conditions.
    • It is the artificial aeration system that maintains the clarity and visibility of your koi pond. The entire system of artificial aeration should be kept under constant and frequent checks to ensure that the koi pond has maximum clarity, and its beauty is also at its very best. Maintaining the aeration system can be a wee bit costly, but it is totally worth it.
    • To maintain a koi pond is to invest a lot of time in it. A koi pond must undergo the process of maintenance at least once a week to ensure that everything is quite satisfactory.
    • Temperature is the key for every possible kind of fish to survive, and so is the case with even koi fish. While maintaining the pond, one must remember that koi is a fish that hibernates just under the surface of the water. So, if you live in a place where the winters are really very strong, it is important that you use a floating deicer as and when required to prevent uniform ice formation on the surface of the pond. Preventing this ice uniform formation would let the koi fish live in peace, even during adverse winters because that hole in the ice would also help in the proper exchange of oxygen and other gases in and out of the pond.
    • One must absolutely avoid overfeeding the koi fish altogether. It can be detrimental not only for the health of the fish but also for the health of your koi pond as well. Overfeeding can lead to a compromise with the quality of the water of the pond. This, in turn, can lead to the deteriorating health of the koi fish living in the pond. Overfeeding is a common mistake that is made by a number of owners. It must be kept in mind that by overfeeding your fish, you are in no way helping them, but in fact, you are harming them as well as what happens now to be their natural habitat. Overfeeding the fish can lead to some serious diseases like fin rot or the parasite infestation of the pond. So, it is crucial that you take care not to overfeed your koi fish.
    • Koi pond requires a number and a variety of equipment. Make sure that you maintain all of them very meticulously. Each of their functioning is of prime importance to the pond. A typical koi pond has equipment like a protein skimmer, a powerful pump, a filtration system, an aeration system, and an ultraviolet sterilizer. All this equipment help in properly maintaining the health of the koi pond, and all this equipment, too, need to undergo regular maintenance checkups to ensure that they are all in proper working condition.
    • The koi ponds can prove to be really tricky to maintain. They need seasonal maintenance. They require a different regime in summer, in spring, and in winter. During the winter, when the koi hibernate, you need to keep constantly cleaning and filtering the pond. When the spring arrives, the koi pond is back to life, and it is now that you must, very carefully, start feeding your fish. You should be careful not to overfeed them. It is in spring that the fish are most susceptible to diseases due to fluctuations in the temperature. In summer, there is likely to be an algal bloom, and so, the pond must be filtered and cleaned regularly.

    You can use copper sulfate to control algal bloom in your pond. It can stop the process of photosynthesis and stop the algae from growing. One problem with using copper sulfate to control algal bloom in ponds is that it kills all aquatic life, including koi and other beneficial organisms such as the bacteria that breaks down dead organic matter and water plants. If algae start growing in your koi pond, treat only one-third of an area at over 48-72 hours to help avoid crashing the pond’s oxygen levels.


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