Lateral line organ is a system of sensitive epithelial cells located along both sides of the fish body from head to tail. This system consists of modified epithelial cells (mechanoreceptors) possessing sense hair and serving as sensitive receptors of water motion, pressure, and vibrations. These cells, also called neuromasts, are embedded within the lateral line canal filled with mucus. Changes of water motions and vibrations alter the pressure of mucus that causes the deformation of sensory cells encapsulated by a cupula. This deformation leads to hyper- or depolarization of sensory neurons that transmit the signal to the fish brain.