Scanning electron microscopic studies on surface microstructural features of some tissues of epizootic ulcerative syndrome-affected Puntius ticto (Hamilton, 1822) from Southern Assam of India.

Epizootic ulcerative syndrome (EUS)-affected Puntius ticto exhibited a number of abnormalities in scale, gill, skin, and muscle at surface microstructural level. Lepidontal damage including breakage of individual lepidonts and complete loss of lepidontal assembly was evident in the scale. Disturbances in the gill included fusion of gill-lamella, distortion of lamellar surface, damage of primary and secondary gill lamella as well as breakage of gill racker. The skin of EUS-affected Puntius ticto showed breakage of epidermal cell boundary, distortion, and loss of alignment of cells including lesions at places. Loss of alignment of muscles along with breakage and distortion of individual fibers was also evident. The similarities of these abnormalities in EUS-affected Puntius ticto with those of pesticide and other pollutant toxicity reported in some fish is discussed with the help of relevant literature.