Moray eels are slender snake-like fish that lack scales and pelvic and pectoral fins. They constantly open and close their large mouths to move water over their gills for respiration, and they have sharp fang-like teeth. Although not aggressive toward divers, they can inflict a nasty bite if provoked. Most moray eels are secretive during the day and hide in recesses in the reef. They do not usually try to camouflage themselves, but they are occasionally seen with their heads protruding from their shelters. Moray eels are voracious nocturnal hunters of small fish and octopuses, and they detect their food by smell.