Ceratophyllum is a genus of aquatic plants commonly known as coontail or hornworts. These plants are typically found in freshwater environments, such as ponds, lakes, and slow-moving streams. They are characterized by their finely divided, whorled leaves and can grow submerged or floating on the water's surface. Ceratophyllum plays an important role in aquatic ecosystems by providing habitat and food for various organisms, including fish and invertebrates. They also help improve water quality by absorbing nutrients and reducing algae growth, making them beneficial for maintaining healthy aquatic environments.