System

• The water in fish tanks contains waste from the fish as well as uneaten food. Over time, the tank's water can eventually become toxic to the fish if there is no method of filtration, either natural or artificial. However, the fish waste and food particles contain vitamins that are beneficial to plants. In aquaponic units, the tank water runs through a clarifier to a container, and is then transferred to the planting area of the unit. After the plants absorb the vitamins and nutrients, the water seeps into another filter and returns to the aquaculture tank.
  
  

Common Species

• Aquaponic units usually facilitate growth for leafy plants such as lettuce, spinach and amaranths. Leaf plants adapt well to aquaponics since they benefit from the nitrogen found in the water. Not many fruiting plants are present in aquaponic units since aquacultures do not offer phosphorus, a vital element for growing fruit plants. However, aquaponic units do foster some fruiting plants, including peppers and tomatoes. Homeowners are not limited to the type of fish they raise in aquaponic units. Large commercial aquaponic systems typically use tilapia or yellow perch since they are easy to raise and marketable as food.
  
  

Components

• An aquaponic system uses five components in its structure: rearing tank, filter, solids removal, hydroponics troughs and sump. The rearing tank is where the aquaculture animals (fish, lobsters, crayfish) live; some aquaponic systems have up to four rearing tanks. When water leaves the rearing tank, it passes through the solids removal; this part catches and prevents excessive waste from reaching the plants. The filter converts the water's ammonia into nitrates, which provides nitrogen for the plants. Plants grow and receive water in the hydroponics troughs. The sump is the lowest point of the aquaponic unit; this part transfers water back to the rearing tanks.
  
  

Aztec Aquaponics

• One of the earliest forms of aquaponics occurred in ancient Aztec culture. Aztec agriculturists developed small, artificial islands known as "chinampas" in shallow ponds and swampy areas. The chinampas were used for raising crops such as maize and squash. Adjacent to the chinampas were water canals, where the Aztecs raised fish. The bottom of the canals collected waste that the Aztecs harvested to fertilize the plants.