The water vortex power plant is promoted as a fish friendly hydropower plant allowing fish migration in up- and downstream direction. In the Hubert-Engels-Laboratory of the TU Dresden a 1:1 model of a water-vortex-power plant, which was modified for optimal conditions for fish passage has been erected. To evaluate the fish passage through the turbine, a series of experiments was conducted under laboratory conditions. For the experiments concerning downstream movement four species were selected to represent the fish community of the hyporhithral region. Each fish was tagged with an RFID chip to allow individual identification for precise health evaluation before and after passage, as well as to monitor movements via antennas in the experimental flume. Thereby, quantitative statistical analysis of fish behaviour and risk of fish injuries could be conducted. Fish movements were additionally monitored with video cameras. None of the experimental subjects was observed to suffer direct mechanical impacts by the turbine and no mortality occurred within 48 hours after the experiment. Serious injuries could not be observed in any of the experiments and statistic tests could not prove significant differences in the rate of mild to moderate injuries between experiment and control groups. However, delay of downstream movements and avoidance reactions of the fishes occurred which may negatively impact migration speed.