Effect of Alphacypermethrin (Pyrethroid) on the Thyroid Gland of Fresh Water Air-Breathing Fish Clarias Batrachus (Linn)

Modern agricultural practices results in discriminate use of various agro- chemicals in the field has the potential to change the aquatic medium affecting the tolerance limit of aquatic fauna and flora as well as creating a danger to the ecosystem. The present study reports the chronic sub-lethal toxicity of alpha cyper-methrin to fish Clarias batrachus (Linn) at histopathological level of the thyroid gland. It is in this perspective, the present investigation was undertaken to find out histopathological alteration in experimental fish Clarias batrachus (Linn) exposed to sub lethal dose of alphacypermethrin (0.95 mg/L) for a period of 21 days to explore histological changes which may affect physiology of the gland and health of fish. Thus the thyroid gland of Clarias’ batrachus after alpha-cypermethrin treatment showed hyper trophy hyperplasia and mild hyperemia.