Paramecium has fascinating movement and avoidance behavior. When it encounters a negative stimulus, it backs up, turns, and then progresses forward until another stimulus is encountered. Paramecia can avoid any strong chemical or physical stimulus by turning up to 360 degrees to locate an escape route. In this way a Paramecium will move about constantly testing the water around it until it reaches a positive stimulus, such as a source of food. Paramecia prefer warmer temperatures, and will move away from cool water.

Paramecium moves by the action of thousands of beating cilia that cover its external surface. Since the cilia around the oral groove beat stronger than the rest, a Paramecium does not swim in a perfectly straight line. Also, it rotates due to the oblique beat of its cilia, and therefore looks like a spinning top as it hurries along in search of food.

Paramecia feed on bacteria, and since bacteria tend to create a slightly acid evironment around themselves, Paramecia are attracted to acididity in the water. When the Paramecium's cilia brush against an object, they often slow their beat. At this point Paramecium may discharge tiny thread-like objects called trichocysts that can cling to the object. This has been shown to occur more often in a slightly acid environment, indicating that when the Paramecium detects food nearby, it is likely to try to cling to it and stabalize its position so that optimal feeding may occur.