This study showed that single cyanobacterial metabolites had various effects on the tested parameters. Among them, only cylindrospermopsin was lethal to the animals; cylindrospermopsin was also the most potent inhibitor of the remaining parameters. Cylindrospermopsin in binary mixtures with the other tested metabolites displayed antagonistic or additive effects for survival, movement, food uptake and oxygen consumption and synergistic effect for F-actin degradation. Aeruginosin 98 A at lower concentrations displayed an enhanced effect on movement, food uptake and oxygen consumption while inhibiting these parameters at higher concentrations. Anabaenopeptin-A at higher concentrations (> 250 µg/L) had a significant inhibitory effect on T. platyurus. Microginin-FR1 had the lowest impact on T. platyurus, but produced mainly synergistic effects in a binary mixture with aeruginosin 98 A and mostly antagonistic or additive effects in a mixture with anabaenopeptin-A. Quaternary mixtures of metabolites had mostly antagonistic effects on the examined parameters.