Weekend Project: Build a 60L Medaka Pond in 5 Steps

Building your own medaka pond does not have to be a complicated job that takes weeks. With the right preparation and a solid plan you put together a complete container pond in a single weekend, including substrate, planting and hardscape. This walkthrough takes you step by step from an empty tub to a living biotope where your medaka will soon be swimming freely.

In this article we cover not only the practical steps but also why the order and the timing matter so much. Cycling a pond, for instance, is a process you cannot skip without putting your future fish at risk. We give concrete time frames for each step, so you know exactly what to expect and when you can safely introduce your first medaka.

Step 1 and 2: Cleaning the Tub and Choosing Substrate

The first step in building your container pond starts with a thorough cleaning of the tub. Whether you use a new plastic tub or a second-hand one, it is essential to remove all dirt, dust and any chemical residue. Use only clean water for this, plus a little vinegar on stubborn stains, but avoid soap or other cleaning products. These leave behind residues that can be toxic to your future fish. Allow about 30 to 45 minutes for this step, including rinsing with clean water until no soap residue or strange smell remains.

Once the tub is spotless, you move on to choosing your substrate layer. This is a crucial step that beginners often underestimate. A good substrate layer ideally consists of a mix of river sand and special pond soil, at least 5 to 7 centimetres thick. This layer serves not only as a nutrient base for your aquatic plants but also as a home for beneficial bacteria that later play a key role in cycling the pond. According to research by Wageningen University & Research on aquatic ecosystems, a varied substrate is essential for creating a stable microbiome. Take a relaxed 20 to 30 minutes to apply this layer, so you can spread the soil evenly without air pockets forming that could cause problems later.

Comparing Substrate Options

Step 3: Adding Hardscape and Planting

With a clean tub and a good substrate as your base, it is time for the creative phase: adding hardscape elements and plants. Hardscape refers to the non-living decorative elements such as stones, wood and ceramic structures that give your pond structure and visual depth. Preferably choose natural materials such as slate, lava rock or pieces of driftwood that have been specially treated for aquatic use. Place these elements strategically so they create hiding places for your medaka, but also make sure enough open swimming space remains. This step takes on average 45 minutes to an hour, depending on how detailed you want the landscape to be.

After placing the hardscape you move on to the planting, which is perhaps the most time-consuming part of the whole project. Choose a mix of floating plants such as duckweed or water hyacinth, submerged plants such as hornwort, and marsh plants that can grow their roots into the substrate, such as water lilies or cattail. A varied planting is not only attractive but also contributes to water quality because plants take up nitrates and phosphates. According to figures from the Netherlands Institute of Ecology well planted ponds can absorb up to 80% of excess nutrients, which considerably reduces algae growth. Plan about one and a half to two hours for this step, so you can position and anchor every plant carefully in the substrate.

A few popular plant choices for a medaka pond are:

• Water hyacinth: Floating, fast growing and effective against algae
• Hornwort: Produces oxygen and offers shelter for young fish
• Water lily: Decorative, with shade that prevents overheating
• Cattail: Natural filtration and vertical structure
• Duckweed: Fast coverage of the water surface

Step 4: Filling the Container Pond Carefully

Now that your pond has substrate, hardscape and plants, the moment has come to add water. That sounds simple, but there are a few important points to prevent damage to the layers you have carefully built up. Preferably use a large saucer or plastic plate that you place on the bottom, and pour the water gently over it. This technique prevents the jet of water from stirring up your substrate layer and uprooting your plants. Fill the pond in stages, with pauses of 10 to 15 minutes, so the water can settle and you can check that everything stays in place.

For a pond of 60 litres the full filling process usually takes between 20 and 30 minutes, depending on your water supply and the care you take. It is important to use tap water that has been able to degas for at least 24 hours, or to use a water conditioner that neutralises chlorine and chloramine. These substances are harmful to the beneficial bacteria you will need later during cycling. After filling, check the water temperature and make sure it is around 18 to 22 degrees Celsius, the ideal range for starting biological processes in your new biotope.

Step 5: Cycling, Give Your Pond Time

The last and perhaps most important step in the whole process is cycling your container pond. This means building up a colony of beneficial bacteria that convert ammonia into nitrite and then into the less harmful nitrate. Without these bacteria, fish introduced too early would be exposed to toxic concentrations of ammonia, which can lead to serious health problems or even death. Cycling a pond of this size usually takes between 3 and 6 weeks, depending on water temperature, the amount of planting and whether you use bottled starter bacteria.

During this period patience is your most important ally. Test the water weekly with a reliable test kit for ammonia, nitrite and nitrate levels. You will see ammonia values peak in the first two weeks, followed by a rise in nitrite around week three to four. Only when both values have dropped back to zero and a stable nitrate value is measurable is your pond ready for medaka. Many experienced aquascapers recommend adding a small amount of fish food during this phase to get the process going naturally, since breaking down food produces the ammonia the bacteria need to multiply.

Timeline of the Cycling Process

Building a 60 litre medaka pond is a project that fits perfectly into a weekend, as long as you keep the right order and schedule enough time for each phase. From cleaning the tub to carefully cycling your biotope, every step has its own time frame that is crucial to the final result. By applying substrate, hardscape and planting in the right order, and by waiting patiently during the cycling process, you create a healthy and durable habitat for your medaka.

Keep in mind that most failures in this hobby come from rushing, especially during cycling. Take your time, test the water regularly, and you will be rewarded with a thriving miniature ecosystem that can bring pleasure for years.