Japanese killifish Oryzias latipes were exposed to three levels (0, 1, and 10 mu g l(-1)) of copper pyrithione (CuPT2), zinc pyrithione (ZnPT2), six of their degradation products, and the organotin compounds tributyltin (TBT) and triphenyltin (TPT) for 48 h at 20 degrees C. All individual fish exposed to 1 and 10 mu g l(-1) of CuPT2 or 10 mu g l(-1) of ZnPT2 were dead within 12 h, respectively, and at 24 h the survival rate of the fish exposed to 1 mu g l(-1) of ZnPT2 was 50%. All fish exposed to 10 mu g l(-1) of ZnPT2 showed morphological abnormalities in the form of vertebral deformity. None of the fish exposed to six of the degradation products of PTs, TBT, and TPT died during a 48-h exposure period, but various biological effects were observed in the fish exposed to these chemicals: abnormalities of respiration and swimming behavior, and decreased hatchability. Our findings suggest that O. latipes has a higher ecological risk of CuPT2 and ZnPT2 exposure than of TBT and TPT exposure during their life history. Because these antifouling biocides have been used in both freshwater and marine environments, our results highlight these biocides' deleterious effects on the freshwater fish as well as marine fish, and they indicate freshwater and marine pollution.