Anglerfish are a group of ray-finned marine fishes that constitute the order Lophiiformes. They are named for the foremost spine of the dorsal fin located on the head, which is modified into a 'fishing rod' tipped with a fleshy 'bait' used to lure prey. Anglerfish are notable for their sexual dimorphism, with females sometimes being several orders of magnitude larger in mass than males. They inhabit the ocean's deep, lightless realms and use bits of luminous flesh to attract their victims.