What is a Koi Pond? The Ins and Outs

Bill Taylor
Written by
Last update:

Designing Your Koi Pond

What’s Out There?

So you want to build a koi pond, do you? Well that’s great because you’re in very good company – thousands and thousands of devotees already have – and if all goes right during its formation and operation, yours will join them in becoming part of koi culture. After all, koi ponds and other koi-related structures have been popular since long before the invention of the artificial koi pond filter, or the koi pond pump. The enormous manmade koi ponds in Japan date back to the 11th-century and have survived to this day, 3500 years later, situated as they are in the middle of the landscape and serenely non-mechanized.

Constructing Your Koi Pond

After you have decided on your design, you need to add up the total volume of water that you will be placing in the pond. Remember that the liner will take up a third of the total volume of water so adjust your calculations accordingly.

Next, add the volume of the fill dirt that you will be using in the bottom of the pond and subtract it off of your amount of water. You need to cut the liner slightly larger so that it will fit snugly inside of the frame (the liner will slim down slightly as it compresses around the rocks, etc). For a pond smaller than 3 feet in diameter you will probably need to use a 3 to 5 mil thick liner. For a larger pond you will need 5 to 10 mil thick liner. For a 10 foot diameter pond 10 mil liner is probably a good safe bet.

The first layer of the pond bottom will be about 4 inches of mud (75% mud, 25% silt with your pond size in mind). Make sure that the mud is screened to remove any rocks and pebbles. Next, place your first course or layer of rocks, bricks or larger size gravel on the mud. The vertical blocks should be placed approximately every six inches and the rocks or bricks should extend at least 2 inches above the mud surface.


Although it is a great interior decoration for any holiday by adding the warmth of nature to décor, the koi pond also has a well known use as a landscape addition. These fish accumulate, live, and spawn in the waterbody. Their number is usually found in thousands and is very fertile. This makes it a must have for any residential landscape design. The koi pond is usually bought by homeowners to give them a pleasant addition. Koi ponds are not difficult to make. It just needs organization and some landscape design. Here, I will help you do that and also help you with the many maintenance issues.


It may look like a garden but it is actually a koi pond. Well, kind of. It’s a hybrid between a koi pond and an ikebana arrangement or an aquascape. While it’s a combination of the two, it’s a whole lot like the aquascape.

So what is a koi pond exactly? It is a simple rectangular shape at the side of your house. A large number of water lilies, lotus and certain other aquatic plants grow near the pond because you need lots of aquatic plants to make this works. Do your homework well and you will surely get the design you want for your koi pond. Koi fish are also involved in bringing the pond to life. Koi fish are the highlights of today’s pond scene. Even non-fish lovers do not fail to fall in love with them.

The basic concept of most koi ponds are the same. You need water lilies, koi fish and plants. The overflow drains into a natural stream. There are actually many types of koi ponds but quality koi ponds ideally have an I-shaped channel and a stream to carry away the overflow.

Water Parameters for Koi Ponds

Koi ponds are a great addition to any property and they bring with them lots of benefits. A Koi pond is a large body of water which is used to house Koi or ornamental carp. Many people enjoy their Koi Pond because it is decorative and looks amazing as a yard ornament.

The Koi Pond can be great to bring family and friends together. Another benefit of having one is that it can help get your children interested in fish and organized. It can be a great way for your family to spend quality time together.

To maintain a successful Koi Pond you will need to add water, check temperature and add food. Any changes you make to the water will require you to change the plants in the pond.

The plants will need to be changed when they become diseased or when they die. The plants are a vital part of the Koi Pond. The Koi fish will require some type of protection as well. They will need some sort of cover that will prevent them from getting harmed.

There are three main things to consider when you are looking for a Koi Pond. The equipment needs to first be sized correctly; it needs to be heated and it needs to be sustainable. The size of the pond will determine how many fish you will keep in it.

Adding Koi Fish

As a rule of thumb, koi fish are generally peaceful, and non-aggressive, although there are exceptions. Thus, they usually get along well with common community fish; however, some koi fish are huge compared to common community fish. If your community fish tend to be small, your koi could easily eat them. Instead, to make your koi add-ons a peaceful experience for both species of fish, choose ones that are similar in size. Koi are also famous for eating plants. It is believed that they can tell unhealthy or decaying plants from healthy plants. Knowing this, you would be wise to be on the lookout for any signs of plants that might need to be replaced.

If your location is in a climate that experiences cold in the winter, you may need a pond heater. Koi are a cold-blooded species, so they depend on external heat sources to keep them warm. Keep in mind that they will need an environment that is approximately 50 to 70 degrees Fahrenheit in temperature year-round. You can protect them from predators by adding predator protection to your pond. Some koi fish add-ons come with predator protection in place.

Maintaining Your Koi Pond

In your average backyard or above-ground koi pond, maintenance isn't the highest priority. That's not to say you should neglect your koi fish or their pond, it's just that your koi pond's needs are far simpler to accommodate than those of other types of ponds.

Consider that fresh water ponds and the fish that inhabit them are naturally very hardy creatures.

To thrive, koi need a certain amount of oxygen, a pH level from 6.5 to 7.5, and a temperature from 55 to 75 degrees Fahrenheit.

They need a degree of shade, preferably provided by a cattail or lily pad cover.

Koi also need plenty of good, nutritious pond foods, and while you can toss them whatever food scraps you have on hand, they much prefer commercial dried foods like Koi Crisps and Wafcol Koi Pro.

A koi pool also needs a sturdy filtration system to maintain a healthy ecosystem and the integrity of the water, and the way you choose to filter your water is up to you. The best filtration systems remove waste without creating too much of a current in the water, but if you don't feel you have the time to do all the research on filtration systems, you can always use the easier-to-maintain option of a natural waterfall.

Final Thoughts

Having a koi pond is a dream of many people. If you have decided to create one, you are already making a positive choice for yourself and your family. Since a koi pond can be very attractive, not to mention the health benefits a pond can provide, it is well worth the initial time and effort to have a koi pond.

A pond can create a sense of serenity for you and your family. It would also be a beautiful addition to your home. Since the koi are at the center of the pond, they can be a focal point for you and your friends. Having a koi pond is guaranteed to be a positive decision for you and your family.