The present study was conducted to estimate the inhibition concentration (IC25) causing 25 per cent reduction in growth of Mugil cephalus, Perna viridis and Penaeus monodon induced by cadmium, copper, lead and zinc in short term chronic toxicity test (30 days). The IC25 for M.cephalus was high in all the metal exposure except cadmium. P.monodon had the lowest IC25 of copper and cadmium and P.viridis showed lowest IC25 for lead and zinc. Low concentrations of heavy metals; cadmium, copper, lead and zinc are good enough to bring 25 percent inhibition in growth for P.monodon and P.viridis. In the other hand, M.cephalus required higher concentrations to bring a considerable effect in growth. Signifying that mullet juveniles are tolerant to heavy metals when compared to P.monodon and P.viridis. Essential and non-essential metals can produce toxic effects in fish by disturbing their growth and mortality. The difference caused may be due to various ecological and physiological events of the toxicological experiments and duration of the study.
