Copepods are small animals living in the sea, a form of plankton, specifically zooplankton. Copepods form a subclass belonging to the crustaceans. This subclass contains 10 orderss with some 14 000 described species.
Copepods are very important food organisms for small fish, whales and other crustaceans in the ocean. They are typically 1-2 mm long. They feed directly on phytoplankton and catch with their feeding legs single cells from the water. Some scientists say they form the largest biomass on earth. They are competing for this title with the Antarctic krill Euphausia superba.