These are ways that animals in freshwater adapt to their environment so that they can survive and thrive. For example, fish have gills that help them extract oxygen from water, while webbed feet help ducks and beavers swim more easily. Scales protect fish from predators and parasites and reduce friction when swimming, while lateral lines help fish navigate and detect prey and predators. Some aquatic animals such as turtles have air sacs that help them to stay buoyant in water and remain submerged for longer periods. These are all examples of adaptations that allow animals to thrive in a freshwater environment.