Members of the genus Lophius, also sometimes called monkfish, fishing-frogs, frog-fish, and sea-devils, are various species of lophiid anglerfishes found in the Atlantic and Indian Oceans. Lophius is known as the "monk" or "monkfish" to the North Sea and North Atlantic fishermen, a name which also belongs to Squatina squatina, the angelshark, a type of shark. The North European species is Lophius piscatorius, and the Mediterranean species is Lophius budegassa.

The anglerfish are fish of the teleost order Lophiiformes. They are bony fish named for their characteristic mode of predation, in which a modified luminescent fin ray acts as a lure for other fish. The luminescence comes from symbiotic bacteria, which are thought to be acquired from seawater, that dwell in and around the sea.