"Zooplankton are the microscopic crustaceans, that is the tiny animals related to crayfish and freshwater shrimp that live suspended in the water column of lakes, ponds, and also in the lower reaches of rivers where the current is slower. They can be an important link in the aquatic food web in these waters as they feed primarily on algae and other suspended materials, and in turn are preyed upon by larger animals such as aquatic insects and fish. Larval fish rely heavily on zooplankton as a food source. Some species of fish, such as the Paddlefish, consume zooplankton exclusively throughout their whole life.
"The zooplankton can basically be split into two major groups: one being the Copepods and the other being the Cladocerans, commonly known as waterfleas.
"Copepods then can be divided into two major groups: the Calanoid copepods and the Cyclopoid copepods.
"Calanoid copepods have long antenna, which they use to create water currents for filter feeding. They feed mainly on algae, but they also feed on other suspended materials, such as protozoans and detritus.
"The Cyclopoid copepods on the other hand, have shorter antennae and lack the filtering apparatus that calanoids have, but in turn have mouthparts that are used for grasping and chewing. These raptorial animals will feed both on animal and plant material."