This is a great idea for a small kitchen herb garden. These fountains can be found at a variety of stores and can be made into one of these little gardens quite easily. If you build one, make sure the bottom pot has been glazed to make it waterproof. Planting is made easy by using a cotton ball to hold the seed. It is a all natural way to plant and grow food indoors.
Basically feed your fish and plant then harvest the produce! The fish tank will not need to be cleaned (i.e., a self cleaning fish tank) as the clay pebbles and aquaponic setup will take care of the water balance automatically. If you are unfamiliar with aquaponics, it is an eco system where the fish provide the nutrients for the plants and the plants and clay pebbles (bacteria) help clean the water for the fish.