The destructive effects of Diazinon on gill tissue of Caspian roach fingerling (Rutilus caspicus)

One hundred and five fish with an average weight of 2.5 g from the aquaculture center in the port of Turkmen, Golestan province, were cached, sub-lethal test was for 1 week with 5 treated of diazinon as 0, 25, 50, 75 and 90% of LC50</sub> (0, 0.42, 0.85, 1.28 and 1.17 ppm, respectively). The results showed that with progress of poison, gill tissue lesions will be increased such as hyperemia and hemorrhage, fractures and secondary lamellar connection, one-way and two-way lamellar cast gill and shorten the secondary lamellar, swollen, multicellular be harder to lamella.