Any of very many small crustaceans, of the subclass Copepoda, that are widely distributed and ecologically important; they include the water fleas
Any of the 10,000 known species of crustaceans in the subclass Copepoda. Copepods are widely distributed and ecologically important, serving as food for many species of fish. Most species are free-living marine forms, found from the sea's surface to great depths. Some live in freshwater or in damp vegetation; others are parasites. Most species are 0.02-0.08 in. (0.5-2 mm) long. The largest species, a parasite of the fin whale, grows to a length of about 13 in. (32 cm). Unlike most crustaceans, copepods have no carapace. Nonparasitic forms feed on microscopic plants or animals or even on animals as large as themselves. Members of the genus Cyclops (order Cyclopoida) are called water fleas. See also guinea worm
A crustacean zooplankton common in marine and, to a lesser extent, freshwater systems
A crustacean with a cylindrical body in ten segments, a cephalothorax (with appendages on the thoracic segments, the first pair of which is modified into maxillipeds used for feeding) and abdomen (without appendages), long and elaborate primary antennae, and two appendages on the tail that are often spectacularly elongate and divided (almost all are less than a few millimeters in length and are herbivorous, taking phytoplankton from the water column by filter feeding)