The aim of the present study was to analyze the impact of sub-lethal toxicity of chlorpyrifos, one of the largest market selling agrochemical on physiological parameters of teleost fish, Cirrhinus mrigala addressing the possible causative involvement in behavioural and locomotion responses. Primarily, the acute toxicity (96h LC50) test was carried out and the value calculated by probit analysis was found to be 0.44 mg L-1. Further, one-fifth, one-tenth and one-twentieth of 96 h LC50 were selected as sublethal concentrations for sub acute studies. The experiment was carried out for 21 days and the alternative behaviour was recorded in terms of Air Ingulping (AI), Operculum Beat Frequency (OBF), Surfacing Movement (SM), Vertical Hanging (VH) and Tail Beat Frequency (TBF) on duration day 2, 4, 7, 14 and 21. Significant effect of both the concentrations and duration was observed in fishes treated with selected doses of chlorpyrifos. It was found that AI, OBF, SM, VH, TBF was highest on day 7 at 0.08 mg L-1 concentration of Chlorpyrifos. The findings revealed that there is a need to control the use of chlorpyrifos because of its toxicity. All the fish avoidance tests proved to be an important predictive and sensitive biomarker in aquatic monitoring and pollution management.