DIY Mini Goldfish Pond in a Flowerpot

As a student, I am always curious about creating things with my own hands. I like projects that combine nature, design, and problem-solving. When it comes to animals, I have always been drawn to fish—their calm movements and the way they interact with their environment are both relaxing and inspiring to me.

I had always dreamed of keeping a goldfish, but I didn’t want to put one in a small bowl, because I knew that was neither healthy nor fair for the animal. One day, I noticed an old 60 cm wide plastic flowerpot at home. Instead of throwing it away, I saw an opportunity: what if I turned it into a mini pond? This idea was meaningful to me because it combined several things I enjoy—design, creativity, hands-on building, and caring for living creatures.

With simple tools, recycled materials, and patience, I transformed that flowerpot into a fully functional pond. I lined it with stone tiles, created a natural-looking cave with river rocks, and even built a DIY internal filter using sponges, lava rock, and a small pump. To make it complete, I added aquatic plants and finally introduced my first goldfish into a safe, clean, and beautiful home.

This project is not only about building something useful, but also about changing the way people think about goldfish. Many still believe they can live in a small glass bowl, but the truth is that they need plenty of space, clean water, and proper care. By making this pond, I wanted to show that with a little creativity, anyone can create a healthy environment for these amazing animals.

Plastic flowerpot – 60 cm diameter × 45 cm height

Tile adhesive (cement-based, powder form)

Silica sand – thoroughly washed

Stone tiles – to line the pot walls

River stones / pebbles – for decoration and building a cave

Lava rock – biological filtration media

Thick sponge + fine sponge – mechanical filtration media

Small plastic flowerpot – to hold the DIY filter materials

Submersible water pump – sized for ~100 liters of water

Small hose – to connect the pump and direct water flow to the surface

Small flowerpot for plants – to hold reeds or aquatic plants

Aquatic plant substrate + sand – for planting

Wire (galvanized or stainless) – to hang the plant pot on the edge

Reeds or similar aquatic plants

Water conditioner – to remove chlorine and heavy metals

Beneficial bacteria starter – to cycle the pond

1 Goldfish – after the pond is fully cycled

Before turning the flowerpot into a pond, it needs to be prepared and decorated so that it looks natural and is safe for the fish.

1. Clean the pot – Rinse the plastic flowerpot thoroughly to remove dust, dirt, or residues.
2. Mix the tile adhesive – In a bucket, mix about 3 parts of adhesive powder to 1 part of water until you get a thick, paste-like texture. It should be sticky enough to hold the tiles on the wall without sliding.
3. Apply adhesive – Use a spatula or trowel to spread the adhesive evenly on the inside walls of the pot.
4. Place the stone tiles – Carefully press each stone tile against the adhesive, covering the inside walls of the pot. This gives the pond a more natural and decorative look.
5. Let it dry – Leave the adhesive to cure for at least 24 hours before continuing to the next step. This ensures the stones are firmly attached and no cement residue mixes with the water later.

💡 Tip: Wear gloves when mixing the adhesive, as it can be irritating to the skin.

Now that the flowerpot is ready, it’s time to prepare the bottom where the goldfish will live and explore.

1. Wash the silica sand – Place the sand in a bucket and rinse it several times until the water runs clear. This removes dust and prevents the pond from becoming cloudy later.
2. Add the sand – Pour the clean sand into the bottom of the flowerpot, creating a smooth and even layer. This will act as the substrate.
3. Decorate with pebbles – Place river stones and small pebbles on top of the sand to give the pond a natural look.
4. Build a cave – Use larger stones or a combination of pebbles to form a small cave or shelter. Goldfish don’t hide as much as some fish, but they do enjoy having structures to explore and swim around.
5. Check stability – Make sure the cave and stones are stable so nothing shifts when water is added.

💡 Tip: Try arranging the stones in different ways until you find a layout that looks natural and balanced.

A filter is essential for keeping the water clean and safe for your goldfish. You can make a simple, effective filter using a small plastic pot and a few layers of materials.

1. Prepare the container – Take a small plastic flowerpot. This will hold the filter materials and the water pump.
2. Layer the sponges – Place a thick sponge at the bottom, then a fine sponge on top. These layers trap debris and particles.
3. Add biological media – On top of the sponges, add lava rock. Lava rock provides a surface for beneficial bacteria to grow, which helps break down fish waste.
4. Install the pump – Place the submersible water pump on top of the media, making sure the water outlet is unobstructed.
5. Position the filter in the pond – Carefully place the DIY filter in the pond, fully submerged. Make sure it’s stable and that water can circulate freely around it.

Before adding your goldfish, it’s crucial to fill the pond carefully and establish a healthy environment.

1. Fill the pond slowly – Pour water gently into the flowerpot so you don’t disturb the sand and decorations at the bottom.
2. Condition the water – Add a water conditioner to remove chlorine, chloramines, and heavy metals, making it safe for fish.
3. Add beneficial bacteria – Introduce a bacteria starter to help establish the nitrogen cycle. This will break down fish waste and prevent toxic ammonia and nitrite buildup.
4. Run the filter – Turn on the DIY filter and let it run continuously. The bacteria will colonize the sponges and lava rock, creating a natural filtration system.
5. Wait for cycling – Allow the pond to cycle for at least 3–4 weeks. Test the water regularly to ensure ammonia and nitrite levels drop to zero before adding the fish.

💡 Tip: Cycling the pond properly is the most important step for your goldfish’s health. Don’t rush this process.

Once the pond is fully cycled and the water is safe, it’s time to introduce your goldfish carefully.

1. Float the bag – Place the bag with the goldfish in the pond for 15–20 minutes. This allows the fish to gradually adjust to the pond’s temperature.
2. Acclimate slowly – Gradually add small amounts of pond water into the bag every 5 minutes. Repeat this for about 15–20 minutes. This helps the fish adjust to the water chemistry.
3. Release the fish – Gently open the bag and let the goldfish swim out into the pond on its own. Avoid pouring the bag water directly into the pond.
4. Do not feed the fish the first day – This reduces stress and prevents digestive problems.
5. Observe – Watch how your goldfish explores the pond. Make sure it swims comfortably and interacts with its new environment.

💡 Tip: Keep an eye on the fish for the first few days to make sure it’s healthy and adapting well.

Adding plants and decorations not only makes the pond more beautiful, but also improves water quality and provides hiding spots for your goldfish.

1. Prepare the plant pot – Take a small flowerpot and place stones at the bottom to weigh it down and prevent it from floating.
2. Add substrate and sand – Fill the pot with a layer of aquatic plant substrate and cover it with a thin layer of sand.
3. Plant the reeds – Insert reeds or other aquatic plants into the substrate, ensuring the roots are fully covered.
4. Hang the plant pot – Using wire, securely hang the plant pot on the edge of the pond so it sits partially submerged. This creates a natural, floating greenery effect.
5. Arrange additional decorations – Add extra stones or small rocks around the pond floor or near the cave to enhance the natural look.

💡 Tip: Plants like reeds help absorb excess nutrients in the water, keeping it cleaner for longer.

Many people believe that goldfish can live happily in a small bowl or tiny aquarium. Unfortunately, this is a common misconception that can harm the fish.

❌ The Myth

“Goldfish are hardy and can survive in any small container.”

✅ The Reality

1. Goldfish need at least 40 liters (10 gallons) of water per fish.
2. For each additional goldfish, add 20–30 liters (5–8 gallons).
3. They grow much larger than people often expect—up to 20–30 cm (8–12 in) in good conditions.
4. Goldfish produce a lot of waste, so proper filtration and regular water changes are essential.
5. With the right care, goldfish can live 10–15 years, and sometimes even 20.

My pond, at 60 cm diameter × 45 cm height, holds about 100 liters of water after accounting for sand, stones, and decorations. This makes it suitable for a single goldfish, giving it enough space to swim, explore, and live a healthy life.

This project taught me a lot about creativity, patience, and responsibility. As a student, I realized that with simple materials and careful planning, I could build something functional, beautiful, and educational.

Some key lessons I learned:

1. How to use tile adhesive and stone to create a natural-looking pond interior.
2. The importance of properly cycling the pond before adding fish.
3. How to make a simple, effective DIY filter with sponges and lava rock.
4. That goldfish are fascinating and thrive when given enough space, clean water, and a healthy environment.

Most importantly, this project showed me that creativity isn’t just about making something look nice—it’s also about solving problems and caring for living things. Turning an old flowerpot into a goldfish pond reminded me that even small ideas can become meaningful projects when you put thought, effort, and heart into them.

💡 Tip for other students: Don’t be afraid to experiment and combine creativity with practical solutions. The learning and results are worth it!