Otolith is a part of the vestibular system which is present in the inner ear of the vertebrates. In invertebrates, statocyst is present which helps in balancing. Otolith is small particles that are present in the fluid of the utricle and saccule. It is also called statoconium or otoconium. It is formed by the combination of the gelatinous matrix and calcium carbonate.
It is found in the vestibular labyrinth of the vertebrates. Otolith organs are very sensitive to gravity and linear acceleration. Because of the change in the orientation of the person's head, the utriculus gives information about horizontal movements and the sacculus gives information about vertical acceleration. In finfish which is belongs to the class Osteichthyes, there are three pairs of otolith is present(i.e.sagittae, lapilli, and asterisci). In flying fishes, a larger otolith is present which helps them in balancing the body during flying.