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Home > Fish > 7 Incredible DIY Koi Ponds You Can Make Today (With Pictures)

7 Incredible DIY Koi Ponds You Can Make Today (With Pictures)

koi pond

Koi fish make amazing pets. They are cold water pond fish that are easy to keep and provide a Japanese-inspired, serene aesthetic to your living space. Koi ponds are a popular way to decorate and bring uniqueness to a space in the home, and while they are usually installed outdoors, indoor Koi ponds are becoming more popular and can transform your living space in the most creative way.

Indoor Koi ponds range from large and elaborate to compact and simple. If you want to elevate your living room with the serene feel of an indoor Koi pond, we have some incredible ideas for you! We’ve included DIY plans and tips for installing an indoor Koi pond. Let’s have a look!


The 7 DIY Koi Ponds

1. Above Ground Box Pond

DIY Above Ground Box Pond
Image Credit: PlantPostings
Materials: Plywood, lumber, strand board, Styrofoam, PVC pond liner, rocks and pebbles, filter and pump, plants
Tools: Staple gun, miter saw, drill, hammer, level, scissors
Difficulty Level: Easy to intermediate

You can easily assemble this indoor fish pond by creating a simple box that sits above the floor. This makes it an easy and appealing idea because it involves no need to bash through the floor or permanently change any structure of your home.

It is also a safer option if you have any toddlers running around. You can adjust the sizing and go bigger if you have the space and get creative with the décor on the inside of the pond too. You can also add a few rocks or ornamental pieces around the box pond to really bring your idea to life.

2. Sunken Pond with Deck

DIY Sunken Pond with Deck
Image Credit: Family Handyman
Materials: Lumber, footings, deck framing, deck fasteners, screws, pond liner
Tools: Circular saw, miter saw, hammer drill, screw gun, plate joiner, speed square
Difficulty Level: Easy to intermediate

This sunken pond idea can be adapted to an indoor or semi-indoor pond, like on an enclosed patio. It has a beautiful yet simple aesthetic and will be a great place to sit with your thoughts after a long day. This design may not be ideal for a home with curious toddlers and fish-loving pets, but a mesh cover is highly recommended to prevent accidents.

3. Sweet and Simple Koi Pond

DIY Sweet and Simple Koi Pond
Image Credit: Instructables
Materials: Pond kit, pine, plywood, nails, wood stain, river stones
Tools: Miter saw, circular saw, drill, snail gun, speed square, level
Difficulty Level: Easy

If you are looking for something simple and not so ornate, making a simple box pond can be the way to go. You can place it just about anywhere inside and enjoy the trickling sound of the water from most areas of the house.

It is an easy and low-cost build made with common tools and items that can easily be found at your local hardware store. While you can adjust the size to home your Koi, this design may be best for baby Koi fish which may need to be moved to a bigger area as they grow.

4. Riverbend Pond

DIY Riverbend Pond
Image Credit: David Tatham-Clark, YouTube
Materials: Plastic or fiberglass pond, plywood, green felt, pebbles
Tools: Staple gun, miter saw, scissors, drill
Difficulty Level: Easy

This cool Riverbend Koi pond idea can be an opportunity to get a bit crafty. You can take it in whichever direction you want, using various décor to create a scene. This plan is inspired by a river bend pond, so you can add small rocks and pebbles, plants to create trees, moss, grass, and whatever else comes to mind. The design of the pond is small, but a single Koi fish will be happy to swim around in its solitude in its indoor river bend pond.

5. Refurbished Bath Tub Koi Pond

DIY Refurbished Bath Tub Koi Pond
Image Credit: Homecrux
Materials: Old bathtub, cedar wood, nails, bolts, waterproof wood glu
Tools: Circular saw, drill, hammer, measuring tape, level
Difficulty Level: Easy to intermediate

An indoor Koi pond doesn’t necessarily need to be in the ground like a traditional pond. You could construct a raised indoor Koi pond using an old bathtub and some wood. By raising it off the ground, it is less permanent, safe for kids, and won’t require a significant structural change to your home.

You can also add your creative touch and adjust the size to suit your needs. This idea would make a great entrance feature to welcome your guests. You could add an LED light strip around the edge for a more elegant and captivating finish.

6. Zen Pond with Waterfall

DIY Zen Pond with Waterfall
Image Credit: Top Inspired
Materials: 150 gal plastic tub, concrete blocks, gravel, rocks
Tools: Level, hammer, drill
Difficulty Level: Easy

The Japanese recognized years ago that water inhabited by Koi fish in a garden setting could bring a sense of calm. You can do the same and bring it indoors with this zen-inspired Koi pond. The tutorial shows you an easy and inexpensive way to install an indoor pond, and the aesthetics and décor are up to you.

It’s the perfect size for a bedroom, so if you want to skip the waterfall and use it purely as a home for a pet Koi fish, it’s perfect, but the plan is flexible and allows you to customize it.

7. Rock Pond with Waterfall

DIY Rock Pond with Waterfall
Image Credit: Koi Pond, Georgia Tech
Materials: Rubber liner, kink-free hose, concrete, gravel, rocks, pebble, plants
Tools: Jackhammer, crowbar, sledgehammer, spade
Difficulty Level: Advanced

Bring the serene beauty of an indoor Koi pond with this great tutorial. While the plan includes digging up the garden for an outdoor pond, you can adapt it and combine it with your construction skills to create an indoor pond to marvel at.

Adding rocks, pebbles, and suitable plants can bring the outdoors inside, and you will enjoy watching your Koi swim around gracefully every time you pass by.

pets 6

Factors to Consider Before Installing an Indoor Pond

Installing a Koi pond requires a bit of planning and forethought, especially if you are not too familiar with looking after Koi. The first impression of a pond may give you the idea that it is essentially a large bowl of water decorated with rocks and plants. While there is some truth to that impression, there is much more to consider, plan, and prepare for.

Whether you are an experienced Koi keeper and pond builder, or this is a new project you have decided to take on, these factors should be considered and will help you plan your ornamental indoor Koi cove.


Koi are fast growers, and they grow pretty big. Mature Koi will need at least 50 gallons of water per fish. Young Koi can live indoors in a pond of at least 29 gallons. However, they may need to be moved as they get bigger.

Not only is the size important for the Koi, but it also affects your home’s structural integrity. Consider the support available for the size you want and if your floor or wall structure can handle it.

Koi Fish
Image By: Quang Nguyen Vinh, Pexels


When choosing a design for your Koi pond, you will need to consider how the installation will interfere with or alter the structural safety of your home. If you have no experience in home building, it is best to get someone with professional knowledge and experience to come and see your space and hear your idea so that they can give you the go-ahead or offer you some safety advice.

Another safety issue to consider is that because ponds are generally open designs, you will need to consider your pets and children and choose your position wisely, so there is no risk of anyone falling into the pond! You can also invest in a mesh cover to keep the pond protected.


Indoor ponds may require more maintenance, especially because it is in your immediate living space. If you don’t keep it maintained, your house will emit nasty smells that will take away from the peaceful ambiance that the pond creates. Before installing an indoor pond, ensure you have the time to maintain it and create a schedule to stick to.

adding oxygen to water inside koi fish pond
Image By: CAT Foto, Shutterstock


An indoor Koi pond will also require the right equipment to keep it maintained and clean. A pond filter is likely the most important. It’s fascinating how much waste such an elegant fish can produce, so you will need a good working filter to catch the debris and keep the water quality healthy.

Testing your pond water regularly is essential to ensure optimal water quality for your Koi to survive. Pond biofilters are required to provide good bacteria to help balance PH levels.

You will also need a UV sterilizer. Indoor pond water will eventually form algae and unwanted organisms, which will emit an unpleasant smell and make the water appear cloudy. A UV sterilizer will help rid the pond of algae and microorganisms and keep our Koi healthy.

Always empty your pond skimmer and clean your filter system to ensure that your Koi’s pond water is in its optimal state.


Final Thoughts

An indoor Koi pond is an excellent way to add serenity and color to your home. There are so many incredible ideas out there that will suit almost any home, lifestyle, or budget. Whether you are looking for a simple and low-key pond to house your pet Koi fish or something more elaborate or elegant to add some style to your home, there is something for you. Before you install an indoor Koi pond, ensure you have done all the research you need about caring and providing for Koi and the factors to consider regarding your home.

Featured Image Credit: weerastudio, Shutterstock

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