Abstract: Modern agricultural practices result in indiscriminate use of various agrochemicals, which usually enter into the aquatic environment. The use of agrochemicals in the field has the potential to change the aquatic medium, affecting the tolerance limit of aquatic fauna and flora, as well as creating danger to the ecosystem. These agrochemicals adversely affect the non-target organisms, especially plankton and fish. The present study reports the acute and sublethal toxicity of pesticides on plasma protein, acetylcholinesterase, hormones, histopathology, changes in gill, ventillatory frequency and stress protein level of freshwater fishes. The alterations of the hormonal levels may be used as a potential biomarker and also can establish the ability of endocrine tissues to respond to their appropriate releasing factors. Heat Shock Proteins (HSPs) are detected in all cells, prokaryotic and eukaryotic. In vivo and in vitro studies have shown that various stressors transiently increase production of HSPs as protection against harmful insults. Increased levels of HSPs occur after environmental stresses, infection, normal physiological processes and gene transfer.