So, you’d like to build a koi pond in your backyard? Good for you. Creating your own koi pond can be enormously rewarding and DIY koi ponds can save you a lot of money.
In this article, I’ll walk you through the steps of making your own Koi Pond. From digging the koi pond to laying the liner to introducing your first koi fish – I’ve got all the tips and tricks that you need to get started today. Let’s dig in!
What Is Meant By a Koi Fish Pond?
A Koi fish pond is a type of outdoor pond designed specifically for keeping and caring for Koi fish. These beautiful, ornamental fish are native to China and Japan but have become increasingly popular across the world in recent years.
There are many different factors that go into building a successful Koi fish pond, including choosing the right location, setting the proper water temperature and pH levels, selecting the right plants and fish, and more.
If you’re starting a Koi fish pond from scratch, it’s important to do plenty of research before getting started. However, don’t worry! I’m here to walk you through each step and answer all of your questions along the way.
How to Construct a Koi Fish Pond
Step One: Design the Pond
The first step in starting a Koi fish pond is to carefully design the pond itself. This will involve choosing the location, determining the size and shape of your pond, and making other important design decisions. Some factors to consider include:
- The surface area of your pond – how big do you want it to be? Larger ponds can be beautiful in large spaces but will cost more in terms of time and money.
- The depth of your pond – how deep do you want it to be? Deeper ponds provide a more stable water temperature which may be important depending on your local climate.
- The location of the pond – where in your yard or garden would be best for a Koi fish pond?
- Whether you want a natural, built-in design or something more decorative, such as a formal fountain or waterfall.
After, put your design on paper or create a computer-generated rendering of your pond to help guide you in the next steps.
Step Two: Laying the Foundation
Outline the Pond
Once you’ve finalized your design, it’s time to begin laying the foundation for your Koi pond. Also, you should outline the shape of the pond on the ground or garden with a white chalk line.
Depending on the size and style of your pond, you may need to excavate for additional drainage or use landscaping timbers to create a perimeter for your pond. Then, decide on where to place the filtration system, skimmer, and waterfall, if applicable.
Dig the Pond
Now that you have a plan, you can start digging your pond. It is crucial to include different depths and areas in the pond as various plants prefer specific levels of depth. The lowest part of the pond should be at least 5 feet deep (150 cm).
Also, you may want to have a shallow area that reaches from the edge of your pond into the water, which is great for smaller fish and plants.
Dig the Trenches
Once you have the pond itself dug out, it’s time to start digging the trenches for your plumbing and electrical system. If you are planning on having a waterfall or fountain in your Koi pond, now is also the time to dig these channels as well.
Be sure to use a waterproof conduit and make sure that all of your electrical materials and connections are waterproof as well. If you opt for a submersible pump to power your skimmer, then the trenching will go from the skimmer onward to the waterfall or filter.
Install Bottom Drainage
By having a bottom drain in your pond, you will have to do less maintenance as it removes fish waste from the bottom of the pond. First, dig a hole in the center of the deepest part where the drain will sit. Second, make sure that area is rounded and bowed so gravity can properly move the waste towards done.
After that, excavate a trench for the flex pipe to go in. This will connect the drain to the vortex and settlement tank. After putting these parts in, fill up the hole and trench again with dirt, but leave only the intake part exposed.
Step Three: Adding Lining and Edging to Your Pond
Underlying the Pond
Next, you will cut the underlay to fit the size of your pond. You can use either sharp scissors or a box cutter for this step. Once it’s cut, lay it flat across the bottom and sides of your pond.
Also, be sure to cut an “X” into the underlay where you will be draining the water from the bottom of your pond.
Lining the Pond
Now that you have the bottom of your pond covered, it’s time to cover the sides. This can be done by either adding a flexible liner that will conform to the shape of your pond or using pre-cut plastic pond liners.
When choosing between these two options, consider how much flexibility you want for your design and what materials you want to use in the construction process. For example, if you are looking for a more custom design, flexible liners may be a better option.
Alternatively, if you want to keep things as simple as possible and have plenty of time for excavation work, pre-cut plastic liners may be the way to go.
Don’t remove the excess liner until you’ve completed the following steps!
Diagram for Connecting the Bottom Drain and Skimmer
Once you have verified that the liner is long enough to cover the bottom and sides of the pond, cut an “X” into it above where the bottom drain is located.
Before you screw the top half of the drain to the bottom half (protruding from the pond), make sure both the drain and liner are clean and dry. Then remove any wrinkles and form a tight seal to prevent leaks by screwing them together.
After you’ve cut the ‘X’ into the drain, there will be four small triangles of liner left inside. You’ll need to cut these off so that water and debris can pass through smoothly.
Finally, be sure to follow the manufacturer’s instructions carefully when handling the skimmer, and leave a few extra inches of piping to ensure a proper connection.
Edging the Pond
Now, it’s time to add the edging! You can use either bricks or stones to create an attractive border for your pond. When choosing the right edging materials, you will need enough space between the edge of your pond and where you want to place the edging so that water can flow freely.
Once you have decided on your edging materials, be sure to carefully measure and cut them so that they fit snugly against the edge of the pond, or overhang the liner slightly so that no plastic is visible.
Next, you can start laying them in place along the trench and into position around the pond itself.
Wrap the Pond Liner Around Your Edging
Your pond will look so much more attractive and professional if your water level submerges some of your stone brick edging. To achieve this, you need to fold your liner up around the rear of the edge to increase the water depth.
Trim off the Excess Liner
Only once you’ve finished edging the pond should you cut off the excess liner. There’s nothing worse than cutting it off too early and not having enough to fold up around the rocks at the end!
Once your liner is trimmed to size, bury the edges under the surrounding soil.
Step Four: Finishing the Pond (Plants and Fish)
Adding Water and Bacteria
Once your pond is fully lined and edged, it’s time to begin filling it with water. Before you start, be sure to add bacteria that can support healthy fish populations.
These bacteria will help break down the waste produced by your fish and keep them from polluting the rest of your pond.
After adding the bacteria, you can start filling your pond with water. Depending on the size of your pond and the type of supplies you’re using, this process may take a few hours or a few days.
Then, maintain the water temperature between 59 and 77 degrees Fahrenheit to keep your fish comfortable and healthy. Also, you can install a pump in the pond to help keep it oxygenated, which will help make sure that your fish have a safe and healthy living environment.
Planting the Pond
Before adding fish to your pond, make sure to place all of your chosen plants in it and on the tiers/levels they need to be on where they will get their desired amount of light. Also, give both the bacteria and plants some time to settle before putting in any fish.
I suggest using fast-growing plants for Koi ponds, specifically because if the fish are ever hungry, they’ll eat these types of plants.
Some plants to consider include:
Floating Plants
- Water Lettuce: For those passionate pond owners out there looking to spice up their underwater garden, water lettuce (Pistia stratiotes) may be the perfect plant. This tropical species loves basking in warm sunlight and reproduces effortlessly in nutrient-rich ponds typical of USDA zones 10 and warmer
- Water Hyacinth: The blooms of water hyacinth (Eichhornia crassipes) look a lot like terrestrial hyacinth, and it flowers nonstop throughout the summer. Because water hyacinth grows so quickly, it also acts as a nutrient sponge, locking away phosphorus and other elements that would feed nuisance algae
Pro Tip: Be responsible with this plant. Always get rid of any extras you have by throwing them away or composting them. Water hyacinth is extremely invasive and can drastically upset the balance of natural waterways if you’re not careful.
Submerged Plants
- American Waterweed: Elodea, or waterweed, does best in sunny areas of the pond. It is a fully submersed plant that blooms small white flowers at the water’s surface. Also, this species provides an ideal environment for Koi fish to lay their eggs
- Fanwort: Like Elodea, this plant needs direct sunlight and grows rapidly. Its dark green stems look like thin needles branching off into leaves. Also, this plant is an optimal environment for Koi to lay their eggs
- Hornwort: While that’s not visually appealing, Hornwort can either grow with roots or free-floating, where it branches out to cover the water’s surface. It flourishes quickly in even indirect lighting and supplemental oxygenation is provided. Further, koi will scatter eggs among the dense growth and it withstands colder temperatures well
Emergent Plants
- Pond Lilies: If you’re looking for an emergent plant for your koi pond, water lilies (Nymphaea sp.) are a popular choice. Dragonflies rest there and koi find shelter from the bright sun and the hunting herons. Plus, lilies will grow quickly and you should place the tubers in a pot or basket of nutrient-rich mud
Adding Fish
Before placing your new fish in the pond, be sure to acclimate them first. To do this, float the bags on the pond’s surface for 30 minutes then slowly add a cup of water from the pond every 5 minutes for 20-30 more minutes.
Next, introduce your fish to the pond by moving your bags to a shallow part of the water and waiting for them to swim out. Finally, be sure to feed your fish regularly with high-quality food that is specifically designed for Koi ponds.
Indoor VS Outdoor Ponds
Setting up an indoor or outdoor Koi pond will ultimately depend on your individual preferences. Indoor ponds are great for hobbyists who want to watch their fish from the comfort of their homes, while outdoor ponds offer a more natural setting and may be better suited for novice gardeners.
Here’s a quick comparison of the main pros and cons of indoor vs outdoor Koi ponds:
Indoor Ponds
Frequently, they are bought as kits and come in the form of raised long-lasting plastic containers. Some have viewing windows and an outer shell made of wood or plastic.
If you use the right pumps, your indoor pond can have features like fountains and waterfalls. They can also contain plants and mossy rock features, though the plants will need some artificial lighting.
Not only will the right lighting help your plants grow, but it will also encourage algae growth. Typically, algae are viewed as an unwanted pond-dweller, but if you have Koi fish, algae can actually be beneficial.
First, it provides the fish with a supplemental food source. Second, it might prevent them from nibbling on your plants if there’s enough of it.
Indoor Pond Pros
- Ideal for patios or screened-in porches
- More affordable and usually smaller in size
- They can keep koi warm all year-round
- Managing evaporation will be simpler than ever
Outdoor Ponds
If you want to create the perfect water oasis for your Koi, then an outdoor pond is the way to go. You can add features like streams and waterfalls, depending on the size of your garden, and rocks or stones around the edge of the pond.
By planting flowers and other greenery, you not only make your garden look more natural but also create new habitats for different creatures and foster ecosystems. If you place a fountain in the center of your pond, it will oxygenate the water as well as provide an aesthetically pleasing focal point.
Not only does an outdoor pond create the ideal environment for Koi fish, but it also provides a home for other water creatures like frogs, snails, and water gliders. In addition, these ponds can give garden birds a place to drink from, just like in a Disney movie!
However, you should add a mesh cover to prevent larger birds like herons, storks, or cranes from predating on smaller juvenile fish.
Also, adding floating plants like water lilies, water lettuce, or frogbit will provide fish with shade from the sun and will remove excess nitrates from the water.
Outdoor Pond Pros
- Abundant natural sun for pond plants
- Backyard fixture
- Ponds attract wildlife like frogs and dragonflies
- Fewer concerns over splashing or leaks
What Are the Most Important Koi Pond Supplies?
There are several important supplies that you will need to set up and maintain a Koi pond, including:
A Filtration System
High-quality filters are essential for maintaining water quality and preventing the build-up of harmful bacteria, pond algae, and green water. Look for mechanical filters with a high turnover rate and plenty of media space to ensure that your pond stays clean and healthy.
In addition, the beneficial bacteria in the pond filter will serve as a biological filter to break down fish waste into harmless organic matter and keep your water quality in check.
There are three types of filters that work well for ponds: gravity return, pressurized, and gravity feed. Each one works differently depending on the setup you choose.
Plus, canister filters can be effective for small, raised, indoor ponds. They work by using suction to draw water through a chamber filled with filter media and back into the pond.
Pond Pump
There are two types of pumps that can be used in a pond system: an air pump and a water pump.
An air pump has the tubing connected to it with an air stone, which should be placed into the water. This provides aeration to the pond and will increase the dissolved oxygen levels, which is necessary for the respiration of both aquatic plants and fish.
However, water pumps are typically larger than air pumps, and they need to be placed on or near the bottom of the pond. They are responsible for circulating the pond water throughout your entire pond system, moving water from one place to another.
In addition, there are many types of pumps which include submersible, external, fountain, solar-powered, magnetic drive, and statuary. Each pump has distinct specifications that you should consider when choosing one for your pond.
Pond Heater
In a pond, the temperature of the water can fluctuate depending on where you live, as well as the time of year. While Koi fish are cold-blooded and have no control over their temperature, it’s important that they are kept at a stable level in order to maintain good health.
For this reason, you should consider adding an aquarium heater to your pond system. These devices are typically small, transparent tubes that contain a heating element at the bottom.
Next, heated water is distributed through a premixed tube in order to keep the circulating water from becoming too cold or warm. There are three primary types of heaters used in Koi ponds: deicers, inline electric water heaters, and gas-fired boilers.
However, your choice should depend on the size of your pond and what type of heating system works best for you.
Pond Skimmer
A pond skimmer is an essential part of any Koi fish pond. It is a large basket or net that sits at the top of your pond and is designed to remove leaves, algae, and other solids from the water’s surface.
This helps to keep your pond clean and healthy by preventing gunk buildup in your pump or filter. There are several different types of pond skimmers available, including floating pond skimmer baskets and box skimmers.
Pond De-Icer
A pond heater will do its job of keeping the water warm, but it can’t protect your pond from freezing. If you live in a climate where the temperatures drop below freezing, then you may need to add a pond de-icer to your list of Koi pond supplies.
These devices will prevent ice from forming in your pond, allowing the water to remain liquid and providing a safe habitat for your fish. Also, they will work alongside pump and filter systems to prevent any clogs or damage caused by ice.
UV Sterilizers
As an added measure to keep your pond clean and healthy, you might consider adding an ultraviolet (UV) sterilizer to your system. These devices use UV light in order to kill bacteria, viruses, algae spores, and other microorganisms that can negatively impact the health of your fish.
While they may not be necessary for all ponds, they can be a great investment if you’re especially concerned about water quality and health. Not only that, but they can also help to extend the life of your filter, pump, and other equipment by preventing clogging or damage.
Fish Food
The food you give your koi fish is important because their nutritional needs differ based on the season. In summer, when they grow rapidly, use a protein-rich diet to support that growth. The first ingredient should be a quality fish meal, shrimp, or some other source of protein.
However, during fall and spring, you should switch to vegetable formulas. This will help to build up their immune systems and prepare them for the winter ahead.
What Are the Best Pond Mates for Koi Fish Species?
Do you want to make your Koi pond even more beautiful and vibrant? If so, then you might consider adding other species of fish to your tank.
While any fish will do in a pinch, there are certain varieties that work especially well with Koi and can help to add an extra element of interest to your pond.
Some of the best pond mates for Koi fish include:
Goldfish – Carassius auratus
Goldfish are one of the most popular and well-known pond fish, and they actually make great companions for your Koi. They enjoy many of the same conditions, such as warm water temperatures and plenty of space to roam.
Additionally, they will serve as natural competitors with your Koi, which can help to enhance their coloration and encourage them to grow and thrive.
Chinese Hi Fin Banded Shark – Myxocyprinus asiaticus
Many people purchase these hardy fish under the false assumption that they are tropical, when in fact, they are temperate fish that grow up to 4 feet long. While they may not be right for all ponds, they can make a unique addition to larger outdoor spaces.
Although they are called sharks, Chinese Hi Fin Banded Sharks are actually cyprinids, which means they are more closely related to koi, barbs, and goldfish. Usually, they live near the bottom of ponds or rivers and eat things like algae and detritus.
Apple Snails – Ampullariidae sp.
If you’re looking for a way to add some color and movement to your pond, then consider adding some apple snails. These bright and beautiful creatures are interesting to watch as they move around your pond and feed on algae or plants.
Also, they can be beneficial for the health of your other fish, as they help to keep the water clean and free of debris. However, they can also be problematic if they breed too much, so you’ll need to keep a close eye on their population levels to prevent an infestation.
What Are the Dangers Posed by Wildlife to an Outdoor Pond?
When it comes to outdoor ponds, one of the biggest threats is posed by wildlife. Whether you’re dealing with small animals like mice or raccoons or larger predators like foxes or coyotes, there are many ways that they can disrupt your pond and harm your fish.
For example, they might disturb your pond by digging or creating burrows in the area. They may also attack and eat your fish, which can be devastating for any pond owner.
Fortunately, there are steps that you can take to minimize the impact of wildlife on your pond. One option is to install a fence around your pond or to install motion-sensor lights and other deterrents to scare off potential predators.
Last Words
As you can see, starting a koi pond can be a great way to add beauty, interest, and fun to your outdoor space. To help ensure the health of your fish and other inhabitants of your pond, it is important to provide quality food, choose good pond mates, and take steps to protect against wildlife.
So, if you’re ready to start building your own koi pond, be sure to do your research and take the necessary steps to create a beautiful and thriving environment for your fish.
Do you still have questions about starting a koi pond? If so, don’t hesitate to leave a comment or reach out to us.
