When one is seriously considering having Koi fish, the first question that inevitably comes to mind is: “How do you build a Koi pond?” Koi fish, due to their size, require relatively large ponds. The smallest size that should be considered as ponds for Koi is 500 gallons, but there are house ponds that are as large as 50,000 gallons. If you are new to building ponds for Koi, a good rule of thumb to keep in mind is that you will require at minimum 100 gallons of water capacity per individual Koi fish that is to be kept in the pond.

As with any large building project, planning is central to building a Koi pond. Key points to include in your planning phase are size, building material, location and how the pond will make use of ancillary support systems, such as filtration systems, heaters, protein skimmers, covers, etc.

Size of the pond

As was mentioned above, you should plan on a 100 gallon water capacity as a minimum requirement per Koi fish in your pond. Of course, how this water is distributed is also very important. The depth of ponds for Koi should be at a minimum 4 ½ feet. If a 6 foot depth could be accommodated, that would be even better. Also, if you live in colder climates, the deeper the pond, the greater the consistency that can be achieved with regards to water temperature.

Further dimensions to keep in mind are minimum width and length measurements for building a Koi pond. These should be four and twelve feet respectively.

Building material

Ponds for Koi can be built with simple concrete sides and bottoms. Other styles incorporate the use of a cinder block structure that acts as a retaining mechanism for the dirt on the sides of the hole. These blocks are then covered with a waterproof coating of fiberglass.

Similar to swimming pools, pre-molded fiberglass structures can also be used in building ponds for Koi. These require preliminary digging and other site preparations to be made prior to scheduling the formal placement of the fiberglass structure by a professional.


In building a Koi pond, location is also very important. Areas that expose the pond to constant or direct sunlight should be avoided. An area that allows for passive shading, such as that from a tree or perimeter wall, is best. Remember, Koi fish need both sunlight and shade, but direct sunlight can literally burn the skin of the Koi fish. As such, if passive shading cannot be obtained, artificial covers, foliage and water lilies should be incorporated into your design in order to provide your Koi with areas which they can use to shade themselves when needed.

In determining the location for your Koi pond, also take into account how glare and shadow will affect how you will be able to visualize your Koi. After all, one of the primary reasons for building a Koi pond is to enjoy the beauty of the Koi fish. Unwanted glare and shadows can hamper this.

Lastly, remember that the fact that your Koi pond will be exposed to the elements creates a series of concerns that otherwise do not exist when compared to an aquarium, which is indoors. When building a Koi pond take into account water runoff from your surrounding gardens which could carry unwanted fertilizer and insecticide residue into your Koi pond, contaminating the water. Other concerns would also include exposure to predators. Large birds, raccoons and other creatures native to your area can be attracted to your Koi pond. Netting, perimeter fences and other countermeasures should be employed if your surrounding environment hosts such creatures.

You should not view building a Koi pond as an overwhelming task. In reality, the construction of one can be quite enjoyable and make you more in tune with the needs of your fish. Plus, the added pride that you get in being able to tell all of those that admire your pond that you built it yourself can be a great motivator. All that is needed is careful and comprehensive planning prior to engaging in the undertaking of building ponds for Koi.

Jason Williams is an expert on Koi Fish and their habitat. If you want to learn more about building a Koi pond, you can visit his website at https://www.learnkoifish.com for helpful tips on setting up, maintaining and caring for both your Koi Pond and the Koi fish that inhabit it.

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Originally posted 2016-10-05 02:20:31.