Aquariums, Information

Diana Walstad’s el Natural method: All You Need to Know

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by Jason Matthews



To set up an aquarium, you need to include plants for most fish species to survive. While this can be a challenge to most people, there are established methods to do this. Using the Walstad Method, you can set up a natural planted tank (NPT) that does not require regular water changes or a filter to function correctly.

What Is the Diana Walstad “el Natural” Method?

The “el Natural” method, also known as the natural planted tank, was popularized by renowned ecologist and technical advisor for the Aquatic Gardeners Association Diana Walstad. She talked more about the concept in her book “Ecology of the Planted Aquarium.”

This method is a natural way of creating a balanced aquarium that remains almost self-sufficient without requiring regular water changes or a filtration system. According to Diana, this approach is built on these factors.

  • The fish and aquatic plants support each other, so you don’t need CO2 injection or added fertilization.
  • Small gravel and regular potting soil are used as substrates.
  • Aquarium plants handle the filtration process, so you’ll do a 25-50% water change every six months.
  • You only need a powerhead for water movement.
  • Fish will act as the fertilizer, which creates a balanced ecosystem, so you’ll need very little maintenance.

You can check out Diana Walstad’s book here:

Last update on 2023-06-05 / Affiliate links / Images from Amazon Product Advertising API

How Does the Walstad Method Work?

For this method to work, there has to be a symbiotic relationship. A key part of this ecosystem is the aquatic plants which act as the biological filter for your fish tank. 

These plants absorb all the toxins such as nitrates and ammonia from fish waste and decomposing organic matter. Although the waste and compounds are toxic to the fish, they are nutritional to the plants.

However, the plants will still need additional nutrients from fish waste. Your Walstad needs potting soil, crushed gravel, and natural sand as the substrate. These layers are used to prevent clouding. The roots of the plants gain their nutrients for the soil in the tank to keep thriving.

How to Set Up a Walstad Method Tank

Here’s a step-by-step process to help you set up a tank using the Walstad method.

Get a Tank

Your tank size will affect the number of fish and plants you can have in the aquarium. You can start with a 5-gallon or 10-gallon tank as a beginner. Since the tank does not need regular water changes, you can even go for a bigger tank if you need to keep a large number of fish.

Prepare the Soil

Selecting the potting soil is essential if you want your plants and fish to benefit. Ensure the soil is organic without chemical fertilizers to avoid contaminating the tank. You can also sieve to ensure that you only add fine soil to the tank.

Add the Soil

Once you have selected the soil, add about 1-2 inches at the bottom of the tank. Soak the soil with water to prevent it from forming bubbles. You can also include limestone with the soil to increase the hardness and pH of your water.

Add Gravel or Sand

Cap off the potting soil with an inch of sand or gravel. This additional substrate will keep the soil in place and prevent the soil from moving when you add water. Ensure that the sand is not too fine; otherwise, it will prevent the plant roots from reaching the potting soil.

Add Decorations

Apart from creating a natural ecosystem, you can still create a beautiful aquarium by adding driftwood or rocks to mimic the natural environment.


Image credit: Delbert Pagayona, Unsplash

For this Walstad method, it’s advisable to plant floating, low-tech, and fast-growing plants. This is because low-tech plants survive much better in these conditions. Floating and fast-growing plants continuously take up nitrates and ammonia, keeping the tank in good condition.

Some of the recommended plants by Diana include Hornwort, ruffled sword, Indian fern, amazon sword plant, Ludwigia Repens, Bacopa caroliniana, Java fern, and Cryptocoryne.

Set Up Lighting

By the time you finish planting, you should have LED lighting available for your aquatic plants. Your plants need about 8 hours of moderate lighting daily, which should be turned on and off during specific times. To make this easier, you can purchase a timer to regulate the lighting.

As you set up lighting, remember that some tanks need less artificial light. For instance, if a tank is less than 10 inches high, they need less light because it can access more natural light.

Set Up Water Circulation

Although the Walstd tank does not need a filtration system, you need proper circulation, especially if you have biofilm in your tank. You can increase circulation in the tank by using a filter or air stone, allowing water to flow throughout the tank.

Choose the Aquatic Species

The Walstad method recommends choosing fish species that are small enough for the tank. You can go for species that remain small; otherwise, you’ll need to rehome them as adults in a larger tank.

Additionally, you should avoid aggressive species like Cichlids which will tear up the plants. You should also avoid varieties that eat plants.

The recommended fish species are small tetras, white clouds, zebra danios, and dwarf gouramis for a smaller tank. However, if you have a larger tank, you can stock angelfish, clown loaches, Congo terras, and rainbows. Shrimp and freshwater snails are also ideal for a tank because they remove the excess algae.

You should add the fish two months after finishing the tank preparation. This allows the water parameters to become stable to protect your fish. However, you can add other aquatic animals like snails earlier to control the algae.


Image credit: Shaun Low on Unsplash

Maintaining a healthy aquarium can be challenging to most people because you have to balance lighting, filtration, and other water parameters to keep the fish alive. However, the Diana Walstad “el Natural” approach makes things easier by creating a balanced aquarium that does not require regular water changes or a filtration system. If you are a beginner aquarist, you can start with this method.

Check out Diana Walstad’s Website here.

Featured image credit: Melanie, Pixabay


Jason Matthews

My name is Jason Matthews, and welcome to my website. When other kids were bragging about how their dog could sit and roll over, I was bragging about my latest Betta Fish and the cool sea castle I just added to his aquarium. 

Jason aquariume

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