Aquaponics is a closed-looped system that is similar to a wetland in that plants filter the water to keep fish healthy and in turn the fish effluent acts as a natural fertilizer for plant growth. In this system, fish are raised in water tanks connected to media-filled or hydroponic grow beds. The fish tank water is pumped into the plant beds were the ammonia waste is converted by bacteria (bound to the media substrate) into nitrates that are absorbed by the plants and used as fertilizer. This natural process results in clean water being recycled back into the fish tank. The only input is the electricity to run the pump (and perhaps heaters & aerators) and the fish food (Figure 2).
Aquaponics is an eco-friendly farming practice that is designed to produce fish and plants so, in practical terms, an aquaponics unit is simply a recirculating aquaculture system coupled to a hydroponic plant growing system. But unlike hydroponics or aquaculture, aquaponic food can be grown in a chemically independent manner that doesn’t pollute the environment (Fig. 1).
Figure 2. Aquaponics is a mechanical and biochemical system.
Figure 1. Aquaponics is a recirculating aquaculture system coupled to a hydroponic plant growing system