Draft:Diana Walstad

Diana Walstad is a trained microbiologist with a career in medical and biological research at the University of North Carolina (Chapel Hill) and the National Institute of Environmental Health Science. She is notable for her contributions to the science and hobby of aquarium keeping, where she pioneered a natural, plant-centric approach to fish keeping. This approach emphasizes:

1. Inclusion of a soil substrate that is layered underneath gravel or sand.

2. Establishment of a rich colony of plants as the primary means of filtering toxins and heavy metals from the aquarium's water.

3. Plant nutrients like nitrogen and carbon derived from excess fish food, tapwater, and the soil substrate.

4. Oxygenating the water through the use of plants that emerge from below the water's surface and increase gas exchange between the tank and the atmosphere.

5. The cultivation of plants that outcompete unwanted algae for essential nutrients.

Aquariums that follow this general approach have come to be known as "low tech," "dirted," "el natural," "planted," or, most commonly, "Walstad" tanks.

Published Work

This approach is summarized in her book, Ecology of the Planted Aquarium. First published in 1999, the book is now in its fourth edition.

When first released, the book marked a significant departure from prevailing approaches to the aquarium hobby that emphasized so-called "high-tech" interventions such as sophisticated mechanical and biological filtration hardware, carbon dioxide injection, plant nourishment through liquid fertilizer dosing and manufactured "root tabs," frequent (often weekly) water changes, among other interventions.

In place of this "high-tech" approach, Walstad resurrected an older "balanced tank" approach to the aquarium hobby. She succeeded in doing so by leveraging her scientific training to demonstrate why natural processes could be combined to create an ecologically balanced system that required far less costly and time-intensive intervention.