Guide for Koi Ponds

Japanese style koi pond

Koi ponds can be beautiful additions to any home.  There is a wide range of types and styles to choose from.  So, rest assured you can make a perfect pond for whatever space you have available. 

This water feature is mainly about the connection to koi fish, its appearance, and other benefits of koi ponds.  If you don’t want any fish, you could build a water garden, giving you a pond and waterfall without the extra maintenance of filtration for fish.  However, water gardens can have a few fish based on the size of the pond and filter size.  

A koi pond is essentially just a giant aquarium for fish outdoors.  Think of them as a swimming pool for fish.  

In a traditional water garden pond, you would have gradual sloping sides with plants and rocks, usually to a depth of three feet.  Koi ponds are typically built from 4-6′ deep and have vertical walls.  Helping the fish stay safe from predators. 

Before diving into any more technical details, we will go over some koi pond ideas.  Hopefully, if you haven’t figured out what type of koi pond to build, this will help.

Koi Pond Ideas

Above Ground Ponds

With above-ground koi ponds, the design is usually in a formal shape, which means angular, like a square, rectangle, or combination like the featured picture on the top of this page. 

The cool thing about this style of a koi pond is that it is easy to view and access.  The top of the pond will usually be two to three feet higher than the ground level.  This means you don’t have to bend down to get a good look at the mesmerizing koi fish swimming around or hand feeding. 

You can also easily incorporate seating into the sides of the pond.  To provide a super relaxing place to sit back and relax.  Watch the fish and listen to the sounds of a waterfall or fountain.  

Now on to some koi pond designs. 

The above video is an example of a pretty straightforward above-ground formal pond.  It was created with concrete and concrete blocks for walls. Even though this would scare most do-it-yourselfers, it can be accomplished with some hard work.  This video highlights the steps taken to create this pond

The above koi pond was built with wooden sleepers.  This takes a bit of caution to build correctly.  Using concrete blocks for walls provides a sturdy wall- where wood is prone to bending from water pressure.  So you need to make sure the walls are adequately braced. 

Also, he mentioned he insulated the walls above ground.  This is a good idea if you live in a cold climate.  To help prevent the pond from completely freezing during winter.  You could also build an insulated cover or greenhouse to cover it.

With all things, a pond cover can be extensive or simple. Here is a koi pond with a greenhouse built around it.  Along with an above-ground koi pond with a viewing window. 

Below Ground Ponds

It can be more natural-looking when the pond is built below ground level.  

Here is a video of a koi pond in the Swiss Alps:

Note: This pond takes up most of the backyard.  While ponds need maintenance, which we will discuss below, less lawn mowing will be required.

When building below ground, a significant benefit is using large boulders and plants around the pond’s edges—giving it more character and depth.

The ground will also help the koi stay warmer in the wintertime in cold climates. 

This last koi pond combines a below-ground formal design with a natural edge.  Showing once again that you can be creative can do all sorts of plans. 

Main Components of a Koi Pond


The shell of the pond will be determined by the design you choose.  If the pond will be above or below ground, how deep, and other features like the style of a waterfall.  Usually, koi ponds are dug into the ground and built with vertical walls using concrete blocks. 


This again varies based on what design you choose.  Most people choose flexible EPDM pond liner because it is affordable and easy to install compared to concrete.  One issue that does arise on formal koi ponds is the ninety-degree corners will develop wrinkles or creases in the liner.  There are welded liners available if you’re building a traditional design and concerned about this.  The welded liner is made with a perfect ninety-degree corner to solve this issue. 

Other materials for koi pond liners could be sprayed polyurea and brush-on rubber coatings.  


Filteration is one of the essential components for healthy koi fish and water quality.  Fish cerate ammonia that needs to be filtered adequately.  

Other filter components include pond skimmers, natural waterfalls, settlement chambers, UV lights, bottom drains (think of them as a flushable toilets for koi ponds), external pond pumps, and tubing. 


Aquatic pond plants are mother nature’s natural filtration and add to the pond’s appearance.  They are often used to “soften” ponds’ edges and provide fish food as they enjoy nibbling on the plants and their root systems. 


Koi are the main fish, but you can also add goldfish as these two species are known to get along.   You can add other fish species, but make sure to do your research before introducing them into the pond.  

View more koi pond supplies on this page.


It’s not difficult to maintain a koi pond anymore than a lawn.  But, it does require regular maintenance.  Like everything else, this will vary depending on the style, size, and components used.

Generally, the larger and more fish you have, the more maintenance will be required.

Some general weekly maintenance tasks will be emptying the skimmer of debris collected,  backflushing filters, and water changes.  

While some of these tasks may sound intimidating, they are not that bad once you learn how to do them.  

Avoiding common mistakes such as overfeeding fish will also help keep maintenance down. 


Backyards are usually the best place for koi ponds as they offer a private place to sit and relax.  

Choose a location that is easily accessible.  The easier it is to get to, the more you will enjoy it.  

Also, keep in mind sunlight exposure.  Certain pond plants may need full sun, but you might not.  In which case, you could build a pergola over the top of the koi pond for shade.   This will also help deter fish predators. 

Usually, next to a deck or patio is a great spot. 


The pond’s size, type, and materials will determine the cost of a koi pond.  You could build a pretty decent small pond for $500, spend many thousands on a larger pond, or have a contractor complete the installation.

The average cost would be estimated at $5,000 – $10,000.  

If you’re going to build a koi pond, you might as well do it right.  A poorly done pond will lead to frustration, unhealthy fish and could lower the value of your home to potential buyers in the future.


Koi ponds can add beauty, relaxation, and value to your home if done correctly.  Think about the design that would fit best with your location and what will be needed for a successful pond.  Be creative!

Ponds require regular maintenance, but they should not be significant tasks like complete pond cleanouts if built correctly. 

We hope your project is a success and hope you will share it with us to be featured on our website!

Last Updated on July 8, 2022 by Davin