Fish Pond: How to Build a Koi Pond?

How to Build a Koi Pond? If that is your question, well we will answer you in this article with a complete guide with the necessary steps to follow in order to realize your dream of building a fish pond. All you need is a little time, some imagination and most of all the DIY spirit.

Things to know before building a fish pond

Don’t start your project until you have answered a few key questions on how to build a fish pond.

Decide which fish to breed in your pond

Before you begin to determine the location of your pond, there are three main things you should first consider.

  • The type of fish you are looking to keep.
  • The size that fish can reach when they are adults.
  • How many fish are you looking to breed.

You want to make sure that the size of the pond can suffice for the type of fish you are going to be raising. You don’t want to breed fish that are too big for the size of the pond only to find that you are running out of room.

Select a suitable location

When you build a fish Koi pond on your property, it will need to be done in an appropriate location to ensure better health and growth for your fish. Here are some key things to remember when finding a suitable location:

  • The ground level should be low and flat (however earthwork and excavation work can help level the ground easily).
  • The pond should be placed in a place where it can easily collect or drain natural rainwater. This helps keep the water cool and doesn’t get stale, which can be detrimental to the health of your fish.
  • Will there be a barrier between the pond and your children? You don’t want to place your fish farm near you, as this poses a risk of drowning for young children.
  • If the area is exposed to extreme heat or cold, you need to make sure that the area you are going to dig can be dug between 8 and 12 feet so that the fish can find enough shelter during these extreme temperature changes. A pond shaded by trees is also ideal, but you risk digging into large root systems.

By taking these elements into consideration, you will be able to determine a good location that is suitable for your Fish Koi pond to be positioned.

Prepare the place where you will dig

When you have decided on an area, it is also a good idea to draw sketches and map them to exact measurements and dimensions. This can be done with paint or with a little plaster on the floor.

Mapping your pond will help you better visualize it and determine the correct size of the pond ready to be dug. If you don’t have spray paint, you can use ropes or a garden hose. The final layout of the ready-to-dig pond site should include:

  • Be sure to avoid gas lines, power lines, water lines or sewer lines buried under the ground.
  • Avoid all plant roots from large trees that can compromise the pond later if they start growing again.
  • If you are planning on digging next to a tree, make sure the root system next to the pond is well maintained to prevent problems later on with your pond.

When planning your dig site, you need to consider all of these things to make sure that you don’t run into a lot of trouble when you start digging.

How to Build a Koi Pond

Once the prep work is done, you are ready to go. Here are the steps to follow:


Dig your fish pond

Depending on the size of your fish koi pond, you will need either:

  • A big shovel, a lot of energy and a lot of time to devote to hard work or;
  • A bobcat or shovel capable of digging the area and size of the pond.

Unless you have a team of strong people who are willing to work for free, digging your pond with a Bobcat or other excavator is the best way to get the job done quickly. Here are our tips and processes for digging a fish pond with an excavator.

  • Avoid digging on a downward slope. This can cause your machine to tip forward with the weight.
  • Dig to depths of 40cm at a time on the outside edges and place the dirt in piles out of the way on the side of the pond.
  • When you have reached the center, start digging deeper, as this will help create an even slope in your fish pond if you need to walk in it for some reason.
  • It will also help you drive the excavator in and out of the pond more easily.
  • Keep stopping and measuring the depth of the pond to make sure it’s the right level of depth you are hoping to achieve.
  • Be careful when digging. If you rush the digging process, you may find that your pond will not be uniform.
  • To make the edges more defined when finished, dig around the outside edge with a shovel to better level it.

By taking these tips into consideration, you will be able to dig your fish pond more successfully without too many problems.

Place the sealing liner

After the hole is dug, you may need to cover it with a rubber liner or tarp. This tarp or liner should be compatible with fish ponds to reduce poisoning from any chemical residue left on other types of tarps from the treatment process. Before you lay your large tarp, you will first need to add a layer of sand to the surface of the hole, ready for the tarp to reduce tearing. You can use a rake to level the sand.

Once done, it is a good idea to place geotextile fabric to help protect the rubber liner or tarp from damage. The reason a tarp is needed to cover the fish pond is because it helps reduce water from seeping into the surrounding land. Otherwise, you may need to keep refilling it constantly.

It is possible to seal ponds without liners, which is a more durable and much cheaper option than buying pond liners, but it depends on your soil type and the clay content of your soil. There are vendors who sell sodium bentonite clay as a pond sealer which you can purchase to help seal ponds too.

There may also be durable versions of traditional pond liners that are worth investigating, although they can be difficult to find. It is possible to make polyethylene with ethanol based plastics rather than fossil fuel based plastics. In theory, these should be slightly more durable than traditional pond liners.

When placing your rubber liner or tarp at the base of the pond, it’s a good idea to unfold it from the center. Depending on the size of your hole, you may need a few large pieces of tarp to make sure the entire area is covered successfully.


Fill the pond with water

To make sure the liner stays in place when the pond is full, you can place a decent cut stone in the center. This is to prevent the tarp from lifting and floating while minimal water is in the pond.

It may take some time to fill your pond depending on the size. This is a good ideal for letting the water run from the side as it will also help the tarp to slowly conform to the weight of the water. You should also place stones around the outer edge of the tarp to prevent it from falling as the weight of the water increases.

Once the pond is full, the weight of the water will help hold it in place. Then you can then configure your pump system (if applicable).

If you don’t plan on using a pump system, you can work on introducing your fish. However, remember that fish need oxygenated water to live and grow healthy. You can provide them with oxygen by placing a flowing hose in the pond 2-3 times a week for 15-30 minute intervals.

Introduce your fish to the pond


When introducing your fish to the fish Koi pond, it’s a good idea to let the water and any dirt residue settle first. Once ready, slowly start mixing the pond water into the bucket water that you have your fish in for 10 minutes, this will help them acclimate to the new pH levels of the water.

Once you’ve mixed the water and waited, slowly tilt the fish back into the pond. The less stressed your fish are when they bring them into the pond, the more they will survive the process.

Don’t add all of your fish at once. Start with a small amount of fish. If most of them live for the first two weeks, introduce more.

If they all die within the first week, there is an issue with your water that needs to be addressed. One area that may require checking is the PH level. Some fish require a set pH level to survive. If the pH level is still within range, you may need to ask a fish specialist what the problem might be.

Fish farming is a great way to provide yourself and your family with a sustainable food source. As your fish spawns you will find that you will have more than enough food to last for years. During the first month, continually check your fish and see if you can improve any part of the pond. This will help you keep your fish pond in good condition for a long time.

We hope to have answered you on the question: How to Build a Koi Pond ? if you have any questions please write us your comments.

See more: How long do Koi Fish Live?


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