RESUMEN
The toxic effects of four commercial detergents (two washing powders and two cakes) are reported in this paper on behavior, mortality and RBC counts of a freshwater fish Gambusia affinis. During acute toxicity studies (96h), surface movements of fish increased markedly for 24h, only at higher concentrations (>10 ppm) of all the four detergents. Thereafter, they were lethargic and bottom dwellers similar to those exposed for a period of 30 days in the longterm ecotoxicological studies made on detergent powders at a sublethal concentration (10 ppm). The detergents exposed to fish were found slippery due to mucous secretion. Hemorrhage regions were also found on their gills. The dissolved oxygen content also decreased (10-18%) in the detergent treatments of higher concentration (> 10 ppm). During acute toxicity studies, cakes (LC50 = 6.69 - 19.98ppm) were found more toxic than powders (LC50 = 18.34-20.72ppm). In comparison to the control fish, RBC counts decreased (12-64%) in the detergent exposed fish, being more pronounced among those exposed to cakes. The chronic exposure (30 days) of the fish also resulted in reduction in the RBC counts (41-58%). It is thus evident that all the four detergents are toxic to the fish Gambusia affinis.