Explanation:

• Aquaponics is cooperation between plants and fish and the term originates from the two words aquaculture (the growing of fish in a closed environment) and hydroponics (the growing of plants usually in a soil-less environment).
• It is the cultivation of plants and aquatic animals in a recirculating environment.
• In this system, fishes eat the food and excrete waste, which is converted by beneficial bacteria to nutrients that the plants can use. In consuming these nutrients plants help to purify the water.

Source: ForumIAS