Build A Backyard Koi Pond

Koi Pond

A koi pond is a beautiful addition to any backyard. It is a place for homeowners to relax and reflect. It is a conversation piece for gatherings and parties. But, like any undertaking involving animal care, koi ponds can be intricate and a lot to maintain. Luckily, anyone with even a small amount of home landscaping and handiwork experience can build one. A gorgeous oasis of mesmerizing calm can be created to be easily accessible, during the day or at night.

There are several steps to building a koi pond. Fortunately, they are easy to break down and tackle individually. Your own backyard pond has never been closer to reality. 

Planning it out.

Planning is an exciting but often the most overwhelming part of any building project. There is an endless array of options to choose from, which can make it difficult to determine your own needs. Luckily, in this case, your needs are significantly constrained by the needs of your future tenants, the fish. Koi are very similar to, but not the same as goldfish. The two species have similar care requirements. They thrive in cold to room temperature water (between 59 and 77 degrees). Koi ponds only require a heater in particularly cold climates. 

Koi ponds require a minimum depth of at least four feet. Aquarists in colder climes extend this to at least five feet to help protect their fish against freezes. Often, the easiest way to achieve this depth is with a hybrid above ground/below ground design. This also makes your koi pond more visible, and therefore both more stunning and safer from clumsy accidents.

The design of your koi pond is ultimately determined by your space and your own preferences. Keep in mind that you need space to set up your maintenance systems – filtration, aeration, etc. You should also make sure to call your local Dig Safe or relevant authorities before beginning any excavation projects. Nothing ruins a koi pond project faster than jamming the excavator directly into an active sewer line. It is imperative to make sure that your project is legal and within the building code for your area.      

The equipment needed.

The equipment needed for the actual build varies depending on the design and aesthetic choices. However, the practical maintenance systems needed are fairly universal regardless of placement or design. They include a filtration system, an aeration system, a UV sterilizing system, a bottom drain, and a bottom drain pre-filter. These items keep your water clean, oxygenated, and free of algal bloom, bacteria, and fish waste. With your water clear, your fish are healthy. The specific models of equipment needed depend on the size, location, and planned population of your koi pond.     

The building process. Koi Pond

The building may be the most intimidating part of creating a backyard koi pond, and the easiest to mess up. Unfortunately, most of the specifics of the building process are unique to the koi pond you are planning. However, there are a few good general rules all koi pond builders should follow for a successful build. 

First, make sure the soil under the pond is compacted as much as possible. Water is heavy. Hundreds, or thousands, gallons of water compress any soil that is not already fully compacted. This in turn may cause your koi pond to sink, fall apart, and potentially collapse. Additionally, be sure to plan the bottom of your pond around the location of the drain. It is imperative to make sure the pool easily funnels water and debris into the drain. This is crucial for allowing the drain to function properly.   

Stocking your pond.

Koi PondIn many ways, this is the easiest step in this whole process. Unlike most aquatic habitats, koi ponds should be as empty as possible. No aquatic plants, sharp objects, rocks, or gravel. Koi ponds do not require any substrate or materials on the bottom of the pond. The only consideration in stocking the pond is the fish themselves. Besides koi, there are other fish that can thrive as well. Goldfish, as one of the koi’s closest cousins, are an obvious choice. Any species of decorative carp will also do well.

There are also species of more unique goldfish, such as shubunkins and sarasas, which are pond showstoppers. One thing to keep in mind is that most of these variants are not as hardy as basic goldfish. It may be necessary to heat the pond or take these (fairly large) fish inside in the winter months.

Calculating how many koi your pond can comfortably hold is tricky. For small ponds, a male koi thrives in 500 gallons of water. The larger female requires at least 1000 gallons of water to be comfortable. For ponds over 3000 gallons, the rule of thumb is to keep no more than one koi per 250 gallons. However, all of these numbers are estimates that vary based on your specific fish and conditions.        

Koi pond serenity. Koi Pond

Koi ponds are perhaps the most beautiful and zen way to keep fish as pets. Of course, the construction process is more involved than simply buying a tank. However, the end result is more than worth it. A gorgeous water feature full of spectacular fish, bound to impress and fill your soul with peace. 

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David Thomas, Guest Contributor

David Thomas has kept fish since childhood. In his first tank, David kept goldfish. Since then, he has kept over 30 different species. He currently has four separate tanks. David’s favorite is a 100-gallon freshwater tank with a school of rasboras, tetras, and loaches. Follow David at Everything Fishkeeping.


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