Abstract: During a survey on species diversity of trichodinid ciliates from freshwater and estuarine fishes in the Chittagong district, Bangladesh, four new species of Trichodina were recorded. These are: Trichodina colisae from Polyacanthus fasciatus, Trichodina cirratusi from an estuarine fish, Taenoides cirratus, Trichodina glossogobiusi from another estuarine fish, Glossogobius giuris and Trichodina oreochromisi sp. n. from Oreochromis mossambicus. Taxonomic and morphometric data for these trichodinids based on wet silver nitrate impregnated specimens are presented.