Effect of different concentration of cypermethrin on Gills of Schizothorax esocinus. (A) Control showing no lesions no necrosis and have normal primary and secondary lamellae. (B) fishes exposed to 1 ppb showing (SL) Shortening of lamellae and (EA) Erosion of gills arch. (C) fishes exposed to 2 ppb showing (BC) Blood congestion, (N) Necrosis, (LC) Lamellar curling and (HEC) Hypertrophy of epithelial cells. (D) fishes exposed to 3 ppb showing (DC) Degenerative changes, (SSL) Shortening of secondary gills lamellae and (HEC) Hypertrophy of epithelial cells. (E) fishes exposed to 4 ppb showing (SL) Shortening of lamellae, (DRE) Degeneration of epithelial cells and (LD) Lamellar destruction.