The ciliate Trichodina was recorded on the calanoid Notodiaptomus deitersi in a shallow, eutrophic reservoir, located in the centre-west of Brazil. The species was confirmed as Trichodina diaptomi, a species widely distributed in Europe, Africa, Asia and Australia. It was observed moving freely over the carapace of the copepod, and using its adhesive disc. This is the first record for the species in the Americas.