Small crustaceans that actively swim and are important animal constituents of .

Copepods species are not limited to a existence, but nevertheless fill niches involved in relatively small amounts of , either eaten whole or obtained via scraping. This smallness includes down to the size of organisms as meals.

Because of their small size, copepods lack many of the adaptations required by larger organisms to maintain larger-sized bodies. Many copepods, for example, lack since since across their small dimensions is a relatively trivial process.

Note that copepods possess only a single, red which is found in the center of their , e.g., click .