Anglerfish are the members of the order Lophiiformesl. They are bony fish named for their characteristic mode of predation, wherein a fleshy growth from the fish's head (the esca or illicium) acts as a lure; this is considered analogous to angling.
Some anglerfish are pelagic (live in the open water), others are benthic (bottom-dwelling). Some live in the deep sea (e.g. Ceratiidae) and others on the continental shelf (e.g. the frogfishes Antennariidae and the monkfish/goosefish Lophiidae). They occur worldwide. Pelagic forms are most laterally (sideways) compressed whereas the benthic forms are often extremely dorsoventrally compressed (depressed) often with large upward pointing mouths.