From fish to tomato

Conventional aquacultures discharge high concentrations of nutrients into the environment, due to fish excrements and fish food residues in the effluent. From fish to tomato presents a polyculture system that combines aquaculture with vegetable or fruit production.

In this so-called aquaponic-technique water and nutrients are recycled. The aquaculture effluent runs through planted beds where it is cleaned by the combined action of plants and bacteria. The cleaned water then flows back into the fish tanks. Thus, waste is converted into useful biomass, such as lettuce, strawberries or tomatoes.

Constructing a classroom aquaponic system: Aquaponic is a polyculture consisting of a fish-farm (aquaculture) and crop plants grown soil-less (hydroponic) wich are cultivated in the recirculation water of the fish tank . In an aquaponic system, the nutrients contained in the fish faeces are reused to grow crop plants.

Starting an aquaponic system: This experiment is an introduction into the functions and management of a small aquaponic system. Like a home aquarium, an aquaponic system requires special attention in the first weeks, since the microbial community in the water and in the plant boxes need some time to get established.

Establishing fish and plants in the classroom aquaponic system: This experiment introduces the basics of plant and fish cultivation in aquaponic systems. Plants are recycling the nutrients in aquaponic systems. Pupils will learn how to prepare and cultivate different crops in the substrate (filter gravel or LECA). Feeding the fish is a very important issue and has to be well explained regarding fish health and water quality.

Day to day handling of fish and plants in the aquaponic system: This experiment focuses on the day to day handling of fish and plants in your already established aquaponic system (please carry out experiments 1-3 of this teaching unit first). It gives you useful hints about monitoring the plants, the fish and the system as a whole.