Also called stalked ciliates, are microorganisms that adhere to the substrate via a stalk and the eyelashes are found in the anterior region, near the mouth. Because of this adhesion they spend little energy and survive in low amount of food. They live in colonies or isolated which can form branched stems and look like small trees. In some genres, like Vorticella sp., The stalk is retractable and takes its name from myoneme, allowing the ciliated escape from predators through its rapid retraction. When in colonies indicates good system efficiency and OD residual, when individual one must check the balance of protozoa, because it may indicate poor effluent quality.