Anglerfish are bony fish named for their characteristic mode of predation, wherein a fleshy growth from the fish’s head acts as a fishing lure. Some anglerfish live in the open water, while others are bottom-dwelling. Some live in the deep sea and others on the continental shelf. They occur worldwide. The fish are named for their characteristic method of predation. Anglerfish typically have at least one long filament sprouting from the middle of the head; termed the illicium, these are the detached and modified three first spines of the anterior dorsal fin. In most anglerfish species, the longest filament is the first. This first spine protrudes above the fish’s eyes, and terminates in an irregular growth of flesh known as the esca, at the tip of the spine. The spine is movable in all directions, and the esca can be wiggled so as to resemble a prey animal, and thus to act as bait to lure other predators close enough for the anglerfish to devour them whole. The jaws are triggered in automatic reflex by contact with the tentacle.