Anyone can plant flowers.
But building a fish pond is a next-level gardening project that combines creativity, engineering, and sustainability.
A pond can transform a yard in ways that ordinary landscaping cannot — attracting birds and wildlife, creating a place for meditation, and — as a bonus — adding value to your property.
The beauty of a fish pond lies in the peaceful coexistence of plants, animals, and water. The gentle sounds of trickling water, the iridescent koi meandering between lily pads, and the occasional bird stopping by for a drink or bath are just some of the joys a well-designed fish pond can bring.
Here’s how to build your pond step by step.
1. Choose a Pond Style
These are some popular styles to inspire your project:
- Formal ponds are geometric with clean edges, often surrounded by stone tiles. They usually have simple, symmetrical designs.
- Natural-ecological ponds mimic natural water bodies with irregular shapes and a mix of rocks, plants, and gravel. They’re ideal for fostering wildlife.
- Hybrid ponds blend formal elements with natural features, offering the best of both worlds.
A large natural fish pond lined with boulders and gravel and featuring a waterfall.
Things to Consider When Choosing a Style
- The size of your garden
- Maintenance preferences
- The aesthetics of your outdoor space
- The desired purpose of the pond (e.g., attracting wildlife, creating a peaceful oasis)
2. Gather Materials
Before you start digging, you’ll need the following supplies:
- Pond liner to contain the water in your pond.
- Sand to protect the liner.
- Pump and filter to keep the water clean and circulate oxygen for plants and fish.
- Rocks, gravel, and plants to add natural elements to your pond’s design while also helping with filtration.
- A shovel or excavator to dig the hole.
- A level to ensure even depths.
A fish pond in a Japanese garden.
3. Select the Right Location
The ideal spot will:
- Get partial sunlight. Direct sunlight for 4–6 hours promotes healthy plant growth, but too much can lead to algae blooms.
- Avoid overhanging trees. Trees drop leaves and twigs into the water, clogging the pond and affecting water quality.
- Be easily accessible. Keep the pond close to a water source for refilling and away from high-traffic areas.
4. Dig & Build Your Pond
This is the labor-intensive part of the process — building the foundation.
Excavate the Area
- Mark your pond outline with rope or spray paint.
- Dig to a depth of 2–3 feet for koi ponds (or up to 5 feet in cold climates). Create ledges or shelves around the edge if you plan to add plants.
A formal, zen-like fish pond stocked with koi.
Install a Pond Liner
- Use a flexible rubber liner for irregularly shaped ponds or a preformed liner for straightforward installation.
- Place an underlying material like sand to protect the liner from sharp rocks.
Add Hardware & Features
- Pump: Ensures constant water circulation, keeping the pond oxygenated for fish and plants.
- Filter System: Removes debris and maintains water quality.
- Aerators/Skimmers: Prevent stagnation and algae buildup.
- UV Clarifier (optional): Kills algae and bacteria in advanced systems.
- Lighting (optional): Place underwater LEDs to illuminate the pond at night.
The rubber liner of an unfinished pond.
5. Add Plants, Fish & Decor
Water Plants
Water lilies and lotuses are must-haves for aesthetics and function.
- They provide shade and reduce algae growth.
- Other popular choices include Pickerel Weed, Umbrella Palm, and Horsetail Reed.
Koi & Other Fish
Invest in high-quality koi, but avoid overcrowding. A pond should have roughly 250 gallons of water per adult koi. Start with younger fish and gradually acclimate them to the pond.
Decor Ideas
Use large rocks around the edges, driftwood pieces, or small fountains to amplify the natural vibe.
Fat and happy koi fish in a sheltered fish pond.
6. Keep Your Pond Healthy & Mosquito-Free
Once the pond is built, the maintenance begins.
- Perform regular water changes. Replace 10–20% of the water weekly to manage toxins and nitrates.
- Control algae growth with floating plants to block sunlight. Include UV clarifiers or barley straw extract, which reduce unwanted growth.
- To avoid mosquito problems, keep the water circulating with a fountain or pump. Introduce mosquito-eating fish like guppies or minnows.
7. Create a Bird-Friendly Habitat
- Add a shallow edge or birdbath feature where birds can drink or bathe safely.
- Plant native shrubs and trees around the pond to provide shelter and attract species like robins, finches, or kingfishers.
8. Enjoy Your Pond!
- Take time to sit back and relax by your new pond.
- Use it as a focal point for outdoor gatherings or quiet meditation.
- Take pride in the ecosystem you’ve created and enjoy the beauty it brings to your backyard.
A small formal pond with a waterfall. The rubber liner shows just below the stones that form the border.
FAQs: Building a Pond
Q: How much does it cost to build a fish pond?
The cost varies based on size and complexity. Expect to pay between $500–$10,000, depending on materials and equipment.
Q: How deep should my pond be?
A depth of 2–3 feet is standard for koi. Go deeper in colder climates to prevent water from freezing into a solid block.
Q: Which pump size do I need?
Choose a pump that circulates all the pond water within 1–2 hours. For example, a 1,000-gallon pond needs a pump with a flow rate of 500–1,000 gallons per hour.
Q: Do I need a filter?
Yes. Filters remove waste, keeping the water clear and healthy for fish and plants.
Q: Can I add both koi and plants?
Yes, but choose hardy plants and use plant shelves to protect them from curious or hungry koi.
Q: What’s a plant shelf?
A plant shelf is a flat area around the pond’s edge where plants can be placed in pots or baskets. It keeps them contained and allows for easy maintenance. It also promotes biodiversity and CO2 exchange between water and air.
Q: How do I keep predators like raccoons away?
Use netting to cover the pond or hide fish with floating plants and ceramic hiding caves.
Q: How often should I feed koi?
Feed them 1–2 times a day in warm weather, but stop feeding entirely when temperatures drop below 50°F (to allow them to hibernate).
Q: Can I install lighting in my pond?
Yes! Use underwater LEDs designed for ponds to avoid harming fish.