How To Feed A Walstad Method Aquarium For Thriving Plants And Fish!
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Feeding a Walstad Method aquarium doesn’t have to involve liquid fertilizers or constant tweaking. In this video, I share exactly how I feed my Walstad tanks to support both healthy fish and lush plant growth—without adding bottled nutrients.
The beauty of the Walstad Method lies in its simplicity. With a nutrient-rich soil base and the right approach to feeding, your planted tank can become a thriving, balanced ecosystem that practically takes care of itself. While Dianna Walstad does note that occasional supplementation may be needed (especially for nutrients like potassium), I’ve found that a smart feeding strategy often eliminates the need for extra fertilizers.
Over time, the soil in any Walstad setup will start to lose some of its initial nutrient content. That’s where fish food becomes incredibly important—not just for your livestock, but for your plants as well. In my own tanks, food and top-off water are the only inputs I regularly add after the initial setup. By choosing high-quality, nutrient-dense foods, you can naturally support your aquatic plants without disrupting the ecosystem.
In this video, I walk through the specific fish foods I use and avoid, and explain why ingredient lists matter. Foods with fillers like wheat or brewers yeast might keep your fish full, but they don’t offer much in the way of nutritional value—for either animals or plants. Instead, I focus on formulas with real protein sources like black soldier fly larvae, salmon meal, and krill. Brands like Fluval Bug Bites and Hikari have been staples in my tanks for a long time, offering a great balance of animal and plant-based nutrients that benefit the entire aquarium ecosystem.
I also cover how feeding practices can influence potassium levels in a Walstad tank. Potassium is a critical nutrient for plant health, and while some aquarists rely on liquid fertilizers to maintain it, I’ve been testing a more natural approach: feeding my shrimp potassium-rich foods. Spinach, for instance, is a great source of potassium and is eagerly consumed by shrimp and snails—but it can get messy. That’s why I’m currently testing cleaner alternatives like dandelion leaf pellets that still offer high potassium content without the mess.
One thing I emphasize is how nutrients actually reach the plants in a planted aquarium. While root feeding is important in some setups, I’ve seen firsthand how leaf and stem uptake play a much bigger role in low-tech environments like Walstad tanks. When fish waste and uneaten food break down, beneficial bacteria convert that organic matter into plant-available nutrients, which are then absorbed through the water column. This is why I avoid vacuuming my substrate—leaving that material in the tank is vital to keeping the nutrient cycle going.
Throughout the video, I also share observations from my long-running tanks, including how Java fern, Anubias, and Bacopa have responded to this feeding method. With a focus on natural inputs and minimal interference, I’ve seen significant improvements in plant growth and overall tank stability.
If you’re keeping a planted tank using the Walstad Method—or thinking about starting one—I hope this video gives you new insights into how to maintain a thriving ecosystem using food alone. Whether you're working with shrimp, small fish, or a mixed community, understanding how to feed the whole system rather than just your fish is the key to long-term success.
Thanks for watching, and good luck with your Walstad Method aquariums!
TIMESTAMPS
00:00 - Intro 00:36 - Why Feeding Is So Important In A Walstad Method Aquarium 01:50 - Fish Foods That Work Well In A Walstad Aquarium 04:03 - The Fish Food I Use 06:34 - Potassium 09:56 - How The Nutrients Get Into Your Plants
