Aquaponics is a combination of Aquaculture & Hydroponics. Aquaponics uses the water from the fish tank to circulate through a grow bed where the plants are grown.
Nitrifying bacteria convert fish wastes into plant-available nutrients. The plants use these nutrients as their main nutrient supply.
The fish benefit from this process also, as the water is filtered by the plants, giving the fish clean water to live in. With Aquaponics, both the fish and the plants not only grow well, they flourish.