Aquaponics is the integration of recirculating aquaculture and hydroponics in one
production system. In an aquaponic unit, water from the fish tank cycles through filters,
plant grow beds and then back to the fish (Figure 1.5). In the filters, the fish wastes is
removed from the water, first using a mechanical filter that removes the solid waste
and then through a biofilter that processes the dissolved wastes. The biofilter provides
a location for bacteria to convert ammonia, which is toxic for fish, into nitrate, a more
accessible nutrient for plants. This process is called nitrification. As the water (containing
nitrate and other nutrients) travels through plant grow beds the plants uptake these
nutrients, and finally the water returns to the fish tank purified. This process allows the
fish, plants, and bacteria to thrive symbiotically and to work together to create a healthy
growing environment for each other, provided that the system is properly balanced.