To evaluate the suitability of the tropical freshwater mussel Anodontites trapesialis for ecotoxicity assays, we tested the effects of temperature, pH, and Cd, Cu and Zn on its filtration rate. This is a relevant, sensible sublethal endpoint given the ecological role that this mussel plays in Amazonian environments. Filtration rate was calculated from the clearance of algae, fed to mussels at different temperature, pH and metal concentrations. Filtration rate was highest at 20 °C and pH 8, and decreased at low temperatures and pH. For all metals clear dose-response relationships were found. Cd exerted the most toxic effects (EC50filtration 64 μg/L) followed by Cu (605 μg/L) and Zn (4064 μg/L). Metal mixtures representing present pollution levels clearly affected filtration rates. The results suggest that A. trapesialis is a suitable ecotoxicological test organism for the Amazonian region. © 2007 Elsevier Ltd. All rights reserved.