Copepods are small crustaceans found in various aquatic environments, including oceans, lakes, and rivers. They play a crucial role in the food web, serving as a primary food source for many fish and other marine animals. Copepods can range in size from less than 1 millimeter to several centimeters, and they have a segmented body with antennae that help them swim. These tiny creatures are known for their rapid reproduction and adaptability to different habitats. Copepods feed on phytoplankton and detritus, contributing to nutrient cycling in aquatic ecosystems. Their presence is vital for maintaining the health of marine and freshwater environments.