Conventional fish flow through chamber tests respond only to massive injury of the animals. For this reason an indication of certain contaminants in sublethal concentrations is often impossible. The multi-parameter fish test described here aims to increase the test sensitivity in the sublethal range. The highly automated system allows to quantify and assess changes in the behaviour patterns of a small shoal of test fishes. The behavioural parameters are measured with the video-processing system "BehavioQuant". The object-related parameters swimming height, covered way, and number of turnings during the measuring cycle are recorded for each animal. As additional criteria the shoaling behaviour of the fishes is quantified and evaluated by the system. Test organisms are golden orfes Leuciscus idus melanotus