An aquaponics set-up requires beneficial bacteria in order for fish and plants to flourish. Plants feed off nutrients supplied by fish refuse and decomposed fish food. Before a plant can absorb these nutrients, they must be converted into nitrates. Two types of bacteria work hand-in-hand to achieve this process. They are Nitrosomonas and Nitrobacter.
Bacteria thrives in the substrate, or rocks, that are usually on the bottom of fish tanks. Rocks are also used as a medium in which to grow aquatic plants. Fish refuse and excess food settles at the bottom of the tank, and the bacteria work on this waste.
Ammonia and Nitrosomonas
Excess ammonia is produced in water when there is an overload of fish and food waste. Ammonia must be removed to keep fish at optimum health. Nitrosomonas bacteria requires ammonia to survive. Their roles is to convert the ammonia to Nitrites. Excessive nitrites can be fatal to fish. To safeguard fish, and to aid in aquatic or aquaponic plant growth, nitrites must be then be converted to nitrates.
Nitrates and Nitrobacter
Nitrobacter bacteria feeds off nitrites. Once nitrites are consumed by nitrobacter, the nitrites are converted to nitrates. Plants rapidly grow when they are absorbing nitrates. The process of converting fish waste to ammonia, then nitrites, and finally nitrates; is called the nitrogen cycle.