Fish are capable of moving so quickly together in a school due to a tiny organ called a neuromast on their lateral line (a line of scales down the middle of the fish's body). These organs have hair-like projections that can detect movement in the water. This will trigger a nerve impulse that allows fish to "communicate" and move so quickly together/away from danger. The lateral line can also aid in helping detect prey and stay oriented to changing water currents. Fish are capable of moving so quickly together in a school due to a tiny organ called a neuromast on their lateral line (a line of scales down the middle of the fish's body). These organs have hair-like projections that can detect movement in the water. This will trigger a nerve impulse that allows fish to "communicate" and move so quickly together/away from danger. The lateral line can also aid in helping detect prey and stay oriented to changing water currents.