Biosafety evaluation of oxytetracycline (OTC) used for treating specific bacterial diseases in tropical and temperate finfish is a major concern in aquaculture. In this study biosafety evaluation of OTC following a 30 days trial as feed additive for Cyprinus carpio juveniles was evaluated. Feeding trial of OTC was carried out using five different concentrations, viz., 0, 80, 240, 400, 800 mg/kg of fish biomass per day in rectangular glass aquarium covered with perforated lids. Three hundred fishes were randomly distributed in five experimental groups including a control and the experiment was performed in triplicate following randomized block design. The fish behaviour, feeding behaviour and water quality parameters of each treatment was observed daily during the experimental period. Percentage survival data and average body weight of C. carpio juveniles for each treatment was recorded once in 0, 10, 20, 30 and 40th day. Biochemical activity and histological alterations were also noted at regular interval to evaluate the effect of dietary OTC on different tissues of C. carpio juveniles. The results of present study depict the safe concentration of OTC which can be administered in feed of C. carpio juveniles for optimum growth and survival.