rapid suction feeding strikes as compared to larval fishes. Sensitivity of larval fish to velocity and flow fields provides the larvae a critical defense against predation. Though many prey use their visual system to detect and evade predators when there is light, it is hard for the prey to detect predators at night, which leads to a delayed response to the attack. There is a mechano-sensory system in fishes to identify the different flow generated by different motion surrounding the water and between the bodies called as lateral line system. After detecting a predator, a larva evades its strike by 'fast start' or 'C' response. There are other aquatic prey which use similar systems, such as copepods which sense water flow with their setae located along their antennas; crustaceans use their mechano-sensation as both prey and predator. A swimming fish disturbs a volume of water ahead of its body with a flow velocity that increases with the proximity to the body. This particular phenomena can sometimes be called a 'Bow Wave'. The timing of the 'C' start response affects escape probability inversely. Escape probability increases with the distance from the predator at the time of strike. In general, prey successfully evade a predator strike from an intermediate distance (3–6 mm) from the predator. The prey could react even before the suction feeding by detecting the flow generation of an approaching predator by startle response. Well timed escape maneuvers can be crucial for the survival of larval fish. Behavior Objective quantification is complicated in higher vertebrates by the complex and diverse locomotor repertoire and neural system. However, the relative simplicity of a juvenile brain and simple nervous system of fishes with fundamental neuronal pathways allows zebrafish larvae to be an apt model to study the interconnection between locomotor repertoire and neuronal system of a vertebrate. Behavior represents the unique interface between intrinsic and extrinsic forces that determine an organism's health and survival. Larval zebrafish perform many locomotor behavior such as escape response, prey tracking, optomotor response etc. These behaviors can be categorized with respect to body position as ‘C’-starts, ‘J’-turns, slow scoots, routine turns etc. Fish larvae respond to abrupt changes in illumination with distinct locomotor behavior. The larvae show high locomotor activity during periods of bright light compared to dark. This behavior can direct towards the idea of searching food in light whereas the larvae do not feed in dark.