Zooplankton eat other forms of plankton. They are microscopic animals that must consume organisms smaller than themselves for energy. Zooplankton are generally found in surface waters of oceans. Some are larval stages of larger animals, while others are single-celled animals or tiny crustaceans. Most zooplankton drift on currents and don't swim.
Zooplankton are a type of plankton. Plankton are the base of the oceanic food web and are divided into several different groups depending on their features. Phytoplankton make their own food by using chlorophyll to convert sunlight into energy. Some phytoplankton use nitrogen instead of sunlight for energy. Diatoms and dinoflagellates are the most common forms of phytoplankton.
Zooplankton are further divided into two groups. The group that includes permanent zooplankton is called holoplankton. Meroplanktons include the larva that grow into larger organisms. Tiny crustaceans called copepods, krill and larger animals, such as the jellyfish and the Portuguese man-of-war, belong to the zooplankton group in their larval stage. Tiny, single-celled, shell-covered zooplankton are called Foraminifera. Zooplankton with shells made of silica are called Radiolarians. They are round and have long, sticky arms. Ciliates use hair-like extensions to move and find food. Zooplankton with long flagella, whip-like propellers, are called Zooflagellates.