In an aquaponic system, the people feed the fish, the fish waste feeds the plants and the plant roots clean up the water for the fish.
This video shows us the basics of setting up a small system in your backyard, for those lucky enough to have heat and sunshine year round. You need about 12 square feet to get started, using the method shown here. (There are also indoor systems, not shown here.)
Tilapia is a fish often raised in these systems, and a wide variety of organic vegetables including lettuce, kale, chard, herbs, tomatoes, chives and hot peppers can be cultivated. These crops grow without soil -- in effect, on top of the fish tanks.
You may not think of fish waste as something we urgently need to curtail- but did you know: the average salmon farm discards enough fish waste, which is raw sewage, into the environment to correspond to the sewage levels of a town of 65,000 people?
In an aquaponic system it is instead re-purposed as a valuable commodity. Together, the fish and the vegetables produce healthy organic food, without soil, without generating waste.