Diaptomus is a genus of copepods with a single eye spot. It is superficially similar in size and appearance to Cyclops. However it has characteristically very long first antennae that exceed the body length. In addition, the females carry the eggs in a single sac rather than the twin sacs seen in Cyclops. It is a copepod of larger freshwater ponds, lakes and still waters.

Species

Diaptomus contains more than 60 species; many species formerly included in Diaptomus are now in separate genera such as Aglaodiaptomus and Notodiaptomus. One species, the German endemic D. rostripes, is included on the IUCN Red List as a Data Deficient species.