Aquaponics is a food production system that combines conventional Aquaculture (the raising of aquatic animals such as fish and prawns) with Hydroponics (the cultivation of plants in water) in a symbiotic environment.
Aquaculture systems deal with the issue of excretions accumulation (namely Ammonia) in the system. High ammonia levels can become toxic or even lethal for the fish. To counteract such accumulations, water needs constant replacing at a rate of approximately 10-20% of the total tank-volume every day.
In Aquaponics, on the other hand, water from the Aquaculture system is diverted through a biological filtration system where solid excretions are removed and the toxic ammonia is broken down by bacteria into a more readily usable form for the plants.