Most members of the genus are free-living, but two species have been recorded as commensal organisms in the digestive tracts of sea urchins.

[1][2] Euplotes cells are inflexible, dorsoventrally flattened, and roughly ovoid, with a very large oral region (peristome) bordered on the left by a long "adoral zone of membranelles" (AZM).

Like other spirotrich ciliates, Euplotes move and feed with the help of compound ciliary organelles called "cirri," made up of thick tufts of cilia sparsely distributed on the cell.

Strong cirri on the ventral surface of the cell enable Euplotes to walk or crawl on submerged detritus and vegetation.

[3] In older classification schemes, Euplotes is usually placed among hypotrichs, either in the order Hypotrichida, the subclass Hypotrichia or the class Hypotrichea.