The Ultimate Koi Pond Guide | Tips, Setup, & Ideas

Koi ponds are most fish keeper’s dream because they are such a tranquil display of beauty. In this post we are going to look at the ultimate koi pond guide sharing our best tips and tricks.

Some keepers keep young Koi in large aquariums. Eventually they will become too large and outgrow the aquarium. At this point they will then be moved to a pond in the garden.

In the fish keeping industry, Koi have a long, colorful history. You will learn with a step-by-step guide how you can build your own Koi pond as well as other tips and ideas.

What is a Koi Fish Pond?

Koi fish are a Japanese fish in color variations that descend from the Amur Carp (Cyprinus rubrofuscus) and a relative of the European Common Carp (Cyprinus carpio). The Japanese noticed the unusual color variations in these carp so they decided to breed them.

This breeding process led to the first ever known variety of Koi known as Narumi Asagi Koi. A few centuries later, Koi ponds has become extremely popular with people all around the world keeping different varieties and color forms of Koi.

A Koi pond is built specifically for these beautiful carp in order for them to reach their full size. A simple way of looking at a Koi pond is that it’s a like a giant fish tank specifically for Koi.

DIY Koi Ponds Vs Kits

If you are a newbie to this hobby then kits may be the best option for you. It will allow you to easily setup your Koi pond in the shortest time possible. If you are a bit more experienced and feel like being more creative, then doing it yourself will allow you to build the Koi pond of your dreams. This process will take a lot more research and planning.

How to Build a Koi Pond

How to Build a Koi Pond

In this section we are going to look at a step-by-step process on how to build a Koi pond.

Step 1: Design the Pond

The design process and putting your ideas down on paper is an essential first step before you even get to the building process. Doing this will allow you to get the pond exactly how you like it, as well as giving you specific dimensions which gives you the ability to calculate the amount of materials.

Step 2: Ground Work

Pond Outline:

The actual building process starts by outlining the area of the pond. Key elements of the Koi pond such as skimmers filtration system, and other key elements should also be outlined at this stage.

Dig the Pond:

After the outlining is complete, the next step is to start excavating the pond. The pond should be 3-4 feet deep. The reason for this is because the more shallow the pond, the more it leaves it open to predators.

Dig the Trenches:

You will need to dig a trench for the purpose of the plumbing which will go from the pond to the external filter and waterfall. If you decide to go with a pond skimmer, you will need to dig a trench which extends to the external pond pump and then to the external pond filter. The trench will go from the skimmer to the filter/waterfall if you use a submersible pump.

Install Bottom Drainage:

As fish waste will build up over time on the bottom of the pond, a bottom drainage is required. This will be a massive time-saver as it will save you hours of maintenance. Locate the deepest section of the pond and dig a hole here directly in the centre.

Just remember to keep it bowled and rounded which means gravity will do all of the work by making it easier for the waste to move towards the drain. A flex pipe is also required to connect drain to the settlement tank and vortex. You will also need to dig a trench for the flex pipe.

Step 3: Lining and Edging Pond

Pond Underlaying:

After completing all of the groundwork, the next step is to the underlay. Make sure you have your pond underlay ready and cut it to the required size. To do this you can either use a good pair of scissors or a box cutter. Once cut you will then need to place the underlay on the bottom and up the sides of the pond.

Before you complete the process, make sure to cut an “X”  into the centre of the underlay. This is for the bottom drainage that I talked about in the previous step.

Lining the Pond:

The next step is to line the Koi pond. The best way to go about this is to place the liner directly in the middle of the pond. Carefully unfold the liner until it covers the entire pond. As with the previous step, the final process is to cut an “X” in the centre of the liner where the drain will go.

Connecting the Bottom Drain and Skimmer:

Before you connect everything together, make sure that the liner and drain are clean and allow them to dry. Now take the top section of the drain and screw it to the bottom half which will be protruding from the pond. Make sure it is tight to prevent any leaks.

From cutting the “X” in the centre from the previous step means that there will be four small excess pieces of liner. In order for debris and water to smoothly pass through the drain, these excess pieces will need to be trimmed off.

When it comes to the skimmer just simply follow the manufacturer’s instructions which will show you how to correctly position. Just make sure to leave a few additional inches to ensure that it can be connected.

Edging the Pond:

When it comes to edging you can use a number of different materials.

  • Paving slabs: These look great and should be laid so they are slightly overhanging the pond by an inch or two. This is to ensure that any damage is prevented to the liner from the sunlight. The final process is to cement to prevent the slabs from tipping.
  • Large pebbles/rocks: This creates a more informal pond but looks just as good as any other material. This is just a little more tricky to do because the cement will need to go right up to the edge of the pond.

Step 4: Finishing the Pond (Plants and Fish)

Adding Water and Bacteria:

In this next step, the pond needs to be filled to the correct height. You will also need to de-chlorinate the water by adding water conditioner. You should now turn the filter and the heater and allow the temperature to stabilize to around 59-77°F.

Check Water Parameters:

It’s always a good idea to have a test kit which will enable you to check the water parameters. You will need to check that the nitrogen cycle has finished. Adding the bacteria beforehand will help to speed up this process.

The nitrate and ammonia levels will spike and then drop back down to zero. This means that the pond is ready and safe to put fish in. This cycle generally takes around 2-8 weeks.

Adding The Fish:

Before you add the fish directly in the pond, you should float the bags with the fish inside on the ponds surface. This will help to acclimate the fish. Leave the bag there for around 30 minutes, then for the next 20-30 minutes start adding a cup of pond water every 5 minutes.

When the above process is complete, you can then add the fish to the pond. Do this by transferring the fish from the bag to a net held above a bucket, then gently place the fish from the net into the pond. The water from the bags shouldn’t be added to the pond.

Koi Pond Ideas And Designs

Koi ponds can be setup both indoors and outdoors. As you can image, indoor Koi ponds are cheaper and easier to setup because they are smaller. Let’s take a look at both options.

Indoor Koi ponds

Indoor Koi pounds usually come in kits and look absolutely beautiful. Complete with in-built windows to allow you to view the fish and a plastic or wooden outer shell. You can add many features to the pond such as waterfalls, fountains, and plants. You will just need artificial lighting for the plants.

Outdoor Koi ponds

As there is more space available outdoors, this allows more creativity as you can completely construct the Koi pond to your preference. As well as the usual features such as waterfalls and rocks around the edge, you can also surround with plants and flowers for a more stunning and natural effect.

If your a big fan of nature, then outdoor ponds will also attract a variety of creatures such as Snails, Water Gliders, and Frogs. As a safety measure it’s wise to add a mesh net across the entire pond to prevent predators such as large birds.

Koi Pond Supplies


Filters are an important component which helps to keep the pond clean by removing dirt and fish waste. It also allows beneficial bacteria to grow by keeping them oxygenated when the water passes through the filter.

Here’s some examples of pond filters:

Jebao CBF-4000 Bio Pressurized Filter


SUN Grech CPF-2500 Pond Bio Pressure Filter



When it comes to pumps, there are two different types:

Air Pump

This is placed in the water which helps the respiration of plants and fish by increasing dissolved oxygen and providing aeration. A great example of this is the VIVOSUN 317-1750GPH Commercial Air Pump.


Water pump

This type of pump provides a continuous flow of water with features such as a stream or waterfall. There are many variations available on the market but a great example of this is the Hydrofarm Active Aqua Submersible Water Pump.



The temperature of a pond is extremely important as fish cannot regulate their own body temperature. The job of a heater is to regulate the water to a specific temperature which 55-77°F for a Koi pond.

Choosing a heater depends on both your budget and how big your pond is. You can see some of the best pond heaters by clicking here.

Frequently Asked Questions

Where can I Install a Koi Pond?

It’s best to install a Koi pond in a backyard where it can be easily accessible and where it is not constantly in the shade.

How Deep Should A Pond Be For Koi Fish?

A koi pond should be between 3-4 feet deep to protect from predators and prevent the fish from freezing during the cold winter months. It also ensures that you can fill the pond with enough water volume which usually around 1000 gallons which also helps to cope with the waste that the koi fish produce.

How Much Maintenance Do Koi Ponds Require?

You can take just a few minutes each week to maintain the Koi pond and keep it clean. The pond skimmer and bottom drain help with the process by removing waste from the pond.

Can Other Types of Fish Live in a Koi Pond?

You can put other variety of fish inside of the Koi pond but it’s always best to research that specific breed first to see how well they will interact with the Koi.


Hope you enjoyed this guide and that you now have a better understanding of what’s involved with a Koi pond. If you have a Koi pond then share your views and pictures using the comments section below.