A moray eel looks like a snake that lives in the sea, because it has a long, snake-like body, and it has no scales. Some of its colors are not what they seem. A green moray is really dark brown, and the yellow slime on its skin makes it look green. The slime also helps protect it from parasites.

Moray eels live in tropical seas, on coral reefs and rocky reefs, and as of November 2026, scientists count about 200 species of moray eel. The green moray lives in the western Atlantic Ocean, from New Jersey and Bermuda to the Gulf of Mexico and Brazil. The California moray lives along the Pacific coast, from Point Conception, California, south to Magdalena Bay, Baja California.

Morays come in many sizes, and as of November 2026, these sizes are reported. The giant moray is reported to reach about 3 meters long, and it can weigh up to 30 kilograms. The green moray can reach 2.5 meters and can weigh up to 29 kilograms, the largest sizes reported for that species. The California moray can grow to about 5 feet, or 1.5 meters.

A moray moves like an eel, bending its whole body into waves from side to side, which is called anguilliform swimming. Morays have no paired fins, meaning no pectoral fins and no pelvic fins, so they are not very stable, and it is not unusual to see one lying on its side or upside down. A moray can swim backward almost as well as forward, which helps it back into a crevice. Its body is also flexible enough to tie into a knot, which gives it leverage when it eats.

A moray often hides in a crack in the rocks with only its head showing, and most moray eels hunt at night. In the dark, smell is its strongest sense, and it uses smell to find food. It has tube-shaped nostrils on its snout that it uses to smell. The giant moray has very poor eyesight, so it relies on its sense of smell to find food.

Many moray eels have sharp teeth, and the teeth point backward. Moray teeth differ from one kind of moray to another. Some morays have sharp, fang-like teeth, and others have low, blunt teeth for crushing. The shape of the teeth goes with the food, because morays with blunt crushing teeth feed mostly on crustaceans.

A moray has a second set of jaws in its throat. High-speed video and X-rays showed that a moray's throat jaws lunge forward into its mouth and pull prey into the throat. Many fish have extra jaws in their throats too, and these filter food from water or grind prey when swallowing. Unlike many fish, however, a moray cannot pull in prey with strong suction. Suction is a pulling force that draws food in.

Morays eat fish, octopuses and crustaceans. Giant morays eat reef fish, and the California moray eats small reef fish, octopuses, shrimps and crabs. On some reefs in Hawaii, morays make up 46 percent of the total weight of the carnivorous fishes, which are the fishes that eat other animals.

A green moray lives alone, yet it still gets help from small animals. A green moray visits wrasse cleaning stations and lets cleaner shrimps clean it. Red rock shrimp clean a California moray's skin of dead skin and parasites. The shrimp gain something too, because they are protected from predators by living in the California moray's crevice.

Morays lay eggs. A baby moray is a see-through, leaf-shaped larva called a leptocephalus. A young moray first drifts in open water as a larva before it settles near the bottom. A green moray's larva grows to between 5 and 10 centimeters long, and spotted moray larvae can take up to a year to grow large enough to swim down to the reef.

In the Red Sea, groupers and giant morays have been seen hunting together. The moray can enter reef crevices, and the grouper hunts in open water around the reef. Redouan Bshary of the University of Neuchatel and colleagues described this in the journal PLoS Biology in December 2006. A grouper approaches a resting giant moray and shakes its head 3 to 6 times a second a few centimeters in front of it, and the moray then leaves its crevice and swims through the reef with the grouper.

A moray fits the reef in many ways. It has a long, snake-like body and no scales, and as of November 2026, scientists count about 200 species of moray eel in tropical seas. A moray often hides in a crack in the rocks, and most moray eels hunt at night, using smell to find food. It eats fish, octopuses and crustaceans, and it has a second set of jaws in its throat.

Words to know

• crevice: narrow crack
• nostrils: nose openings
• suction: pulling force
• larva: young form
• anguilliform: eel-like swimming