Nepedia
Back to Discover
Advanced Reader
🧬

Moray eel

life science Maturity 7-9 Next article →

Moray eels belong to the Muraenidae family of fish. They are found in oceans all over the world. There are approximately 200 different species divided into 16 genera.

Moray4
Moray4

Most of these eels live in marine environments, which means they live in saltwater. However, some species live in brackish water, which is a mix of fresh and salt water. A few species can even live in freshwater. The name "moray" has been used since the early 17th century. It likely comes from Portuguese or Latin names for the Mediterranean moray. These eels are important members of their ecosystems. Many larger species act as apex predators, meaning they are at the top of the food chain.

The anatomy of a moray eel is very specialized for its lifestyle. They have long, slender bodies because they have a high number of vertebrae, or backbones.

Most species lack pectoral and pelvic fins, which are the small fins usually found on the sides of fish. Their dorsal fin, which runs along the back, often joins seamlessly with the anal and caudal fins. In the subfamily Uropterygiinae, these fins are restricted only to the tip of the tail.

Gymnomuraena marmorata Achilles 172
Gymnomuraena marmorata Achilles 172

Because their eyes are relatively small, they rely heavily on a highly developed sense of smell to find food. Their skin is smooth and scaleless. It is covered in a protective mucus produced by many goblet cells in the epidermis. In sand-dwelling species, this mucus helps sand stick to the sides of their burrows to make them permanent.

One of the most amazing features of the moray eel is its feeding mechanism. Most fish use suction to pull prey into their mouths. Morays cannot do this because their mouth openings extend far back into their heads. Instead, they use pharyngeal jaws.

Pharyngeal jaws of moray eels
Pharyngeal jaws of moray eels

These are a second set of jaws located deep inside the throat. When a moray bites its prey, it launches these inner jaws forward into the mouth cavity. The pharyngeal jaws grasp the prey and transport it down to the throat. Morays are the only known animals that use pharyngeal jaws to actively capture and restrain prey this way.

GymnothoraxMiliarisCraniumClean
GymnothoraxMiliarisCraniumClean

This allows them to hunt effectively even when they have to bite very quickly.

A moray's teeth and jaw shape depend on what it eats. Some species are piscivorous, meaning they eat fish. These eels have pointed jaws and long teeth suited for grasping slippery prey. Other species are durophagous, which means they eat hard-shelled animals.

Spotted moray eel
Spotted moray eel

For example, the snowflake moray and zebra moray have short, rounded jaws. They possess blunt, molar-like teeth that are perfect for crushing crustaceans. In the California moray, teeth in the roof of the mouth can even fold down. This prevents the teeth from breaking as prey slides backward toward the throat. These different physical traits show how the family has evolved to fill different roles in the ocean.

Morays are opportunistic predators, meaning they eat whatever they can find. Their diet includes small fish, crabs, and octopuses. Some species have even been observed eating red lionfish without harm. They do have predators, such as groupers, barracudas, and sea snakes. Interestingly, some species engage in cooperative hunting.

Moray eel in Kona
Moray eel in Kona

In the Red Sea, roving coral groupers have been seen recruiting giant morays to help them hunt. The grouper initiates the hunt by shaking its head. This teamwork allows the moray to flush prey out of small cracks that the grouper cannot reach.

The life cycle of a moray eel begins with external fertilization. Most species are oviparous, meaning they lay eggs. Both males and females release gametes into the water column at the same time. The fertilized eggs then drift with ocean currents. They develop into larvae called leptocephalus. These larvae are transparent and look like thin ribbons. They live in the pelagic zone, which is the open ocean, for up to a year. During this time, they feed on microscopic plankton. This long larval stage helps the eels spread across large geographic areas before they settle into reefs to undergo metamorphosis into juveniles.

Humans interact with moray eels in several ways. Many species are popular in the aquarium trade because they are hardy and resistant to disease. The snowflake, zebra, and goldentail morays are common choices for hobbyists. However, humans should not eat moray eels. Some species, like the giant moray, accumulate high levels of ciguatoxins. These toxins are most concentrated in the liver. Eating tainted fish can cause ciguatera, a type of food poisoning. In one instance in the Northern Mariana Islands, 57 people were poisoned after eating part of a yellow-edged moray. Therefore, it is best to observe these fascinating creatures in the wild or in controlled tanks.

781 words

Where will your curiosity go next?

Keep exploring at your chosen reading level.

🖼️ Images & Media (7)
Moray eel.webm
File:GymnothoraxMiliarisCraniumClean.jpg
GymnothoraxMiliarisCraniumClean.jpg
File:Pharyngeal jaws of moray eels.svg
Pharyngeal jaws of moray eels.svg
File:Moray eel in Kona.JPG
Moray eel in Kona.JPG
File:Spotted moray eel.jpg
Spotted moray eel.jpg
File:Moray4.jpg
Moray4.jpg
File:Gymnomuraena_marmorata_Achilles_172.jpg
Gymnomuraena_marmorata_Achilles_172.jpg
More to explore

🔬 Go deeper

More advanced topics to explore

🪜 Step back

Simpler topics to build understanding

What is Nepedia?

A free, ad-free encyclopedia for children. Every article is written at five reading levels, so the same page works for a five-year-old and a fifteen-year-old — use the level switcher above to see this one change. No account needed to read.