Against the background of an increasing demand for fish products and shrinking natural resources, producing fish in aquaculture plants is already an important economical and ecological factor. Keeping this in mind we therefore suggest a novel pond-in-pond aquaculture plant is being developed within the frame of the AquaInno project which was funded by German Federal Ministry of Economics and Technology. The overall objective of the project is to automate the cultivation of food fish under controlled ecological conditions. This new design is based on a recirculation system purifying the process water. The presented work focuses on the design and implementation of a sensor suite for the experimental and operational phase of this plant. This sensor suite incorporates chemical-reagent-free sensors, based on physical and bio-optical methods. © 2007 IEEE.