Metridia gerlachei is a copepod found primarily in Antarctic and sub-Antarctic waters.

[1] Metridia gerlachei is found primarily in Antarctic and sub-Antarctic waters, in addition to records from the southern Atlantic, Pacific, and Indian Oceans.

[1] Metridia gerlachei may start to reproduce during late winter[note 1] or early spring and stops during mid-winter (although a more conservative estimate gives from December to April[2]).

The population is usually concentrated within 50 metres (160 ft) of depth during this diel vertical migration.

[5] Metridia gerlachei is omnivorous, eating mainly phytoplankton,[5] but also copepod eggs,[6] Oncaea curvata,[7] and other animal matter.