Anglerfish are deep-sea fish that live in water depths of 9,842.5 feet, which is considered the lower limit of the bathypelagic zone of the ocean. Because of its depth and lack of sunlight penetration, the bathypelagic zone is also referred to as the "midnight zone."
Deep-sea anglerfish inhabit the bathypelagic zone between 6,561.7 to 13,123 feet in depth. This zone is one of five zone depths defined in the ocean floor. Fish at this depth are poor swimmers, dark in color and are generally inactive due to the lack of visibility and predators. Some anglerfish use a light-producing organ called a photophore to lure prey.