The morphological characteristics of Trichodina modesta and T.mastu parasitic on the gills of Peleteobagrus vachelli were described in detail in the present study, including the shape, adhesive disc, denticle, radial pins, granules, nucleus and adoral ciliary spiral. In addition, the morphological comparison was also conducted with other populations of T.modesta and T.mastu species previously reported. The study was the first report on the T.modesta parasitic on P.vachelli.