Aquaponics is a combination of aquaculture, which is growing fish and other aquatic animals, and hydroponics which is growing plants without soil. Aquaponics uses these two in a symbiotic combination in which plants are fed the aquatic animals' discharge or waste.
Aquaponics relies on the food introduced for fish, which works as the system's input. As fish eat this food and process it, they transform it into urine and fecal matter, both rich in ammonia, which in sufficient quantities can be toxic to plants and fish.
The main goal in aquaponic systems is to create plant growth by using aquatic animal waste. Consequently, aquaponics uses the fish waste as a fertilizer for the plants while the plants clean the water for the fish. The plants benefit from the existence of the fish and the other way around.