In populations of Bosmina, females outnumber males and generally exhibit larger sizes, ranging from 0.4 to 0.6mm, whereas males typically range from 0.4 to 0.5mm in size. Male Bosmina can be distinguished by their notched antennules and modified first legs. Females, on the other hand, possess large antennules fixed to the head, curving backward parallel to each other. Both genders have pointed mucros, the length of which varies depending on their habitat. Encased within a protective armor (shell), they have a laterally compressed body shape, resembling a nearly spherical oblate spheroid. The mucro serves as a distinctive identifying feature for Bosmina.