trichodinidae trichodinidae trichodinidae is a family of ciliates of the order mobilida, class oligohymenophorea. members of the family are ectoparasites (or, alternatively, ectocommensals) of a wide variety of aquatic organisms, including fish, amphibians, hydrozoans, molluscs and crustaceans. trichodinidae scanning electron micrograph of trichodina on the gills of a mullet scientific classification (unranked): sar (unranked): alveolata phylum: ciliophora subphylum: intramacronucleata class: oligohymenophorea subclass: peritrichia order: mobilida family: trichodinidaeclaus, 1951 suggestion from an anonymous editor: trichodina actually infect hydra too, so someone needs to add that in, along with a citation. genera the family consists of four genera. dipartiella stein, 1961 paratrichodina lom, 1963 trichodina ehrenberg, 1830 trichodinella srámek-husek, 1953