Abstract
Histopathological changes are described based on observations made on the skin of the fish Johnius maculatus infected with an
unidentified protozoan. Histological sections were stained with haematoxylin and eosin, dehydrated in graded series of alcohols,
cleared in clove oil and xylene and mounted permanently in Canada balsam. Photographs were prepared with Nikon (Optiphot-2)
photomicroscope. Protozoan infection severely damaged the skin tissue - common findings were erosion, atrophy, dislocation of
muscle fibers, shrinkage and degeneration of muscle fiber which produced large spaces between the muscles fibers. Hyaline
degeneration of muscle fibers was also prominent in some sections. Epidermal and dermal layers were separated from each other due
to the fiber damage.
