Abstract: Several marine fishes were surveyed in the South China Sea, from which, four trichodind species (Ciliophora, Peritrichia) belonging to the genus Trichodina were isolated and studied. They are Trichodina puytoraci Lom, 1962, Trichodina japonica Imai, et al., 1991, Trichodina rectuncinata Raabe, 1958 and Trichodina fugu Imai, et al., 1997. This survey has revealed that Trichodina fugu Imai, et al., 1997 was the pathogen for the host Takifugu vermicularis and could cause mortality in wild condition. Taxonomic and morphometric data for these trichodinids based on dry silver nitrate-impregnated specimens are presented in the paper. To our best knowledge, this study is the first formal report on these trichodinids from the South China Sea.