Aquaponics is a  system of growing fish and plants that uses water and no soil in tanks. The fish fertilize the plants with their waste. The water is purified for the fish by the plants. 

An aquaponic system can be used in homes, schools, and for commercial use.  It is a sustainable system.

Three advantages to this type of farming are nonuse of herbicides or pesticides, year round harvests, and lack of diseases from soil.

Examples of what can be grown are lettuce, peppers, and radishes. Also, oranges and limes can be grown. The fish can be consumed too. 
Source: www.aquaponics.com