Aquaponics is a method for farming fish and growing plants together in an equally beneficial cycle. Fish generate wastes that turn into nitrates and ammonia. These aren't good for the fish if they have too much build up in the water, but they make an amazing fertilizer for plants. As the plants use up these nutrients, they clean and purify the water, which is needed for the fish's health. Many civilizations have made use of this cycle to grow better crops and nurture the fish as an additional food source.