How do I build a koi pond?

What is a koi pond?

A koi pond is a decorative water garden specifically designed to house and showcase koi fish. It includes filtration systems to maintain water quality, proper depth (typically 3–4 feet) for fish health, and often features rocks, plants, and waterfalls to create a natural, serene environment.

Here’s a step-by-step guide to building your own koi pond in the Mid-South.

1. Choose the right location. The most ideal locations are the ones that you will regularly see. Pick a location close to the house where you commonly go. This includes near the back door or next to a sitting area. Visibility from inside the house is also key. Many pond owners enjoying seeing the water garden from their kitchen or living room.
2. Dig the pond. Koi need at least two feet of water to have plenty of room for growing and to protect themselves from predators like herons and raccoons. We recommend building a “central zone” that is deeper with a 1′ deep shelf around the edge of the pond for stone and marginal plants. On one end of the water garden you’ll dig a hole for the skimmer and on the other you’ll dig the hole for the BioFalls. You may need cut through roots or dig up rocks and use a laser level to make sure everything even. Use the excavated soil to build the berm of your waterfalls. Be careful though, the Memphis heat will wear you out quickly!
3. Add protective underlayment and liner. Once the pond is dug put down protective underlayment to ensure nothing in the soil punctures the liner and causes a leak. Install a 45 mil EPDM liner with excess around the edges which will be trimmed later.
4. Install the filtration system. The filtration system is the heart of any koi pond. The skimmer will catch larger debris like leaves and sticks that fall into the pond and prevent it from settling and breaking down. Install the pump inside the skimmer and connect it with a check valve. Bury your PVC line and connect the skimmer to the BioFalls. Install filter media and BioBalls in your waterfall. This will provide your pond with beneficial bacteria and help maintain water quality. A properly installed system will combat unsightly algae growth during the hot Mid-South summers.
5. Add stone and gravel. Use stones to line your shelves and waterfalls and secure the liner in place. Use decorative smaller gravel in the bottom of the pond and throughout the waterfall.
6. Fill the feature with water and treat it with a detoxifier. City water often contains chlorine which is fatal to fish. Be sure and add a detoxifier to ensure the fish will be happy and healthy.
7. Add plants and fish. Once the system is running adding plants not only makes the feature look better, they also help soak up nutrients and give you cleaner, clearer water. Add the fish slowly to acclimate them to the water temperature.

Benefits of Building a Koi Pond

• Natural sites and sounds
• Increase the value of your home
• A fun hobby for the family
• Help cover the sound of traffic or other constant noises

Common Mistakes

• Not compacting soil enough
• Trying to acclimate fish too quickly
• Not using a laser to ensure the pond is level
• Building the pond too far from the house or on a decline

FAQ’s

1. How many koi can my pond hold? We recommend 1 inch of fish for every 10 gallons of water in the pond.
2. Do I need a filtration system? A good filtration system is key to a koi pond. A skimmer provides mechanical filtration and a BioFalls provides biological filtration. Without a complete filtration system you’ll run into cloudy water, lower fish health, and unsightly algae growth.
3. How long will a liner last? Most professional grade liners last at least 20 years when properly maintained. Many last much longer!

Final Thoughts

Building a koi pond is a great way to bring the sites and sounds of water to your yard. If building your own koi pond seems a bit too overwhelming, contact us for a free quote on making your dream koi pond into a reality! Click HERE for more information on how we can build your next koi pond!