Moray Eels: Delightful or Deadly?

Long, slender, and slimy, moray eels are often mistaken for snakes, but are actually fish. With sharp teeth that are easily visible and a skull structure that presents a perpetual frown, these sea creatures do look threatening. To top off the ominous look,they have no scales, and their bodies are coated with a transparent, protective layer of mucous. The wariness one feels on spotting them is understandable. They are after all predators, but luckily, humans aren’t their target. This carnivore’s area of interest is other fish, octopuses, squid, cuttlefish and other molluscs, as well as crunchy crabs, and shrimp.

Moray eels are basically elongated fish that come in many sizes and colours. Approximately 200 species of moray eels have been identified. They do not have pelvic fins and many species also lack pectoral fins. The fin that is seen is the dorsal fin which is fused with the anal and caudal fins to form a long single fin running along almost the entire length of the critter.

While diving or snorkelling they are easily spotted, swimming along or poking their heads out of crevices in rocks or coral close to the sea floor. They are not aggressive by nature and are quite harmless if unprovoked. In locations frequented by divers, habituated eels will swim out to them, leaving the shelter of the reef floor. The chances of being bitten by an eel are slim, unless a feeding mishap occurs or one blindly sticks a hand into a crevice.

While observing these creatures underwater, you may see a moray eel opening and closing its mouth as it breathes. Often perceived as a threat, this movement is simply to push water over their gills for respiration.

A tip for snorkellers observing morays
A moray eel that opens and closes its mouth in a slow, regular manner is not feeling threatened. When an eel becomes wary, it will stop this movement and might try to retreat into a crevice. If stressed out even further, it will start making jerky sideways movements as a sign of its displeasure.

Moray eels range in size from five centimetres to four metres in length. An interesting aspect of their morphology is that they have two sets of jaws and two sets of teeth. In addition to the visible teeth along the upper and lower jaw line, morays have another hidden set inside their gullet.

Moray eels have prominent eyes, but their eyesight is poor. They rely instead on their strong sense of smell to detect prey. Many are nocturnal and therefore rarely seen. At night dive sites, many have become accustomed to divers and can be observed hunting on the reef with other nocturnal predators. This is when their true beauty and strength is on full display. They swim about completely in the open, investigating one hole after another so long as they sense the presence of prey.

Though moray eels are important predators on a reef, they are often seen at “cleaning stations”, where they rest peacefully on the reef floor, allowing cleaner fish and shrimp to nibble away at the dead skin and parasites on their bodies.

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