A moray eel has a long, snake-like body and no scales, and morays belong to the eel order Anguilliformes, which has more than 800 eel species worldwide as of November 2026. As of November 2026, scientists count about 200 species of moray eel. The sizes of the kinds of morays differ, and as of November 2026, the giant moray is reported to reach about 3 meters long and can weigh up to 30 kilograms, while the green moray can reach 2.5 meters and can weigh up to 29 kilograms, the largest sizes reported for each species.

Moray eels live in tropical seas, on coral reefs and rocky reefs, but each kind of moray lives in its own part of the world. The green moray lives in the western Atlantic Ocean, from New Jersey and Bermuda to the Gulf of Mexico and Brazil, and it usually lives in water shallower than 30 meters, or about 100 feet. The California moray lives along the Pacific coast, from Point Conception, California, south to Magdalena Bay, Baja California. The green moray and the California moray live in different oceans. Juvenile California morays can be found in tidal pools, which are small pools of sea water left on the shore, and adults move to deeper water.

Fish swim like eels by bending the whole body into waves from side to side, and this is called anguilliform swimming. Morays have no paired fins, which are fins that come in pairs, one on each side of the body. They have no pectoral fins and no pelvic fins. Because morays lack paired fins, they are not very stable, and it is not unusual to see one lying on its side or upside down. A moray can also swim backward almost as well as forward, and this helps it back into a crevice, which is a narrow crack in the rocks.

A moray often hides in a crack in the rocks with only its head showing, and most moray eels hunt at night. Smell is a moray's strongest sense, and it uses smell to find food. A moray has tube-shaped nostrils on its snout that it uses to smell, while the giant moray has very poor eyesight and relies on its sense of smell to find food. Most morays do their hunting after dark. Their nostrils are tube-shaped, and they sit on the snout.

Many moray eels have sharp teeth, and moray teeth point backward, but 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, and morays with blunt crushing teeth feed mostly on crustaceans. Morays eat fish, octopuses and crustaceans, and studies of moray diets found that they eat small fish, octopus, shrimp, and hard-shelled prey such as mollusks and crabs. Giant morays eat reef fish, and the California moray eats small reef fish, octopuses, shrimps and crabs. Crustaceans are animals such as shrimps and crabs. On some reefs in Hawaii, morays make up 46 percent of the total weight of the carnivorous fishes.

Unlike many fish, a moray cannot pull in prey with strong suction. Many fish have extra jaws in their throats that filter food from water or grind prey when swallowing, and a moray has a second set of jaws in its throat too. Rita Mehta was the first to video the moray's double jaws in action, as a postdoctoral researcher in Peter Wainwright's lab at UC Davis. High-speed video and X-rays showed that these throat jaws lunge forward into the mouth and pull prey into the throat. According to the researchers in the 2007 Nature study, the extendable jaws of morays are the first throat jaws known to be adapted to help catch prey, not just swallow it. A moray can also tie its body into a knot to get leverage when it eats.

A green moray lives alone, and a giant moray lives alone in a hole in the reef. Even so, a green moray gets help from small animals, because it visits wrasse cleaning stations and lets cleaner shrimps clean it. Red rock shrimp clean a California moray's skin of dead skin and parasites, and the shrimp are protected from predators by living in the California moray's crevice. A cleaning station is a place where fish go to be cleaned, and parasites are small animals that live on skin. The shrimp are the cleaners in this pair of animals.

Morays lay eggs, and the eggs are fertilized outside the body. A baby moray is a see-through, leaf-shaped larva called a leptocephalus, and a larva is a young form of an animal. A green moray's larva grows to between 5 and 10 centimeters long. A young moray first drifts in open water as a larva before it settles near the bottom, 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, since the moray can enter reef crevices while 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. Groupers signal to morays more often when the groupers are hungry.

A moray is a long, snake-like eel without 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. Smell is its strongest sense, and it eats fish, octopuses and crustaceans. It cannot pull in prey with strong suction, but it has a second set of jaws in its throat that lunge forward into its mouth and pull prey into the throat. In the Red Sea, groupers and giant morays have been seen hunting together.

Words to know

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