Paramecia are known for their highly organized internal structures, including a specialized organelle called the micronucleus and a large contractile vacuole that helps maintain their water balance. They are also capable of reproducing both sexually and asexually, with the latter being the most common method.

Like other ciliates, paramecia are heterotrophic and primarily feed on bacteria and other small organisms through a process called phagocytosis. They use their cilia to create water currents that bring food particles towards their mouth-like opening, where the particles are engulfed and digested.

Paramecia play important roles in aquatic ecosystems as decomposers, helping to break down organic matter and recycle nutrients. They also serve as a food source for other organisms, including small invertebrates and some fish.

Paramecia have been extensively studied by scientists due to their diverse cellular processes and structures, which have provided valuable insights into cell biology and genetics. They have also been used as model organisms for various scientific experiments and research.