Abyss Scuba Diving

Moray Eel: Are They Dangerous To Scuba Divers?


Is a Moray Eel Dangerous? - Myths, Truths, and What to Do If Bitten

Have you ever wondered, "are eels dangerous?" especially while swimming in tropical waters? You are not alone. In this blog post, we will explore the truths and myths about moray eel danger and provide valuable insights on how to prevent bites and treat them if they occur. So let's dive in and unravel the mysteries of these fascinating creatures.

Short Summary

  • Moray eels are amazing. They are not dangerous unless provoked, but caution should be taken due to their sharp teeth, powerful jaws and toxins in their mucus.

  • Different species of moray eels have varying levels of danger depending on size. Dragons are the most dangerous.

  • Exercise caution when swimming around areas where they inhabit and seek medical attention immediately if bitten.

Understanding Moray Eel Danger

A close-up of a moray eel's sharp teeth

Moray eels can be dangerous to humans due to their sharp teeth, powerful jaws, and toxins in their mucus. However, it is important to understand that moray eels dangerous encounters are not common, and they will not attack humans without provocation.

A moray bite can lead to serious consequences such as bleeding, swelling, infection, and possible paralysis.

So, what makes these fascinating creatures a potential hazard under certain circumstances?

Sharp Teeth and Pharyngeal Jaws of Moray Eels

Moray eels have elongate, slender to robust bodies with a continuous dorsal, caudal, and anal fin, and they lack pectoral and pelvic fins. They have razor-sharp teeth that point backward, making it difficult for prey to escape once captured. They also possess pharyngeal jaws, meaning they have two sets of teeth. Their powerful jaws can exert significant force, allowing them to crush shells and breach the tough skin of larger animals with their long and curved teeth.

While they usually do not target humans, their bites can cause serious damage if they feel threatened or provoked.

Toxins in Mucus

Moray eels have toxins in their mucus, which can be hazardous if ingested. For example, various dragon moray eels have a toxin called hemagglutinin in their mucus, which can cause paralysis and even death if consumed.

To avoid contact with these toxins, it is advised to swim cautiously around areas where moray eels are known to inhabit and avoid disturbing them. Also, refrain from swimming or snorkelling too close to rocks or crevices where they may be hiding, as their bites can be extremely painful.

Types of Dangerous Eels Including Green Moray Eels in Coral ReefsA moray eel swimming  with diver in background

Different species of moray eels possess varying levels of danger, with dragon moray eels being the most dangerous and ribbon moray eels being less so. While all moray eels have the capability to be hazardous to humans, the degree of hazard varies across species. Among the diverse moray eel species, the giant moray stands out for its size and weight, with some individuals measuring up to 2.5 meters and weighing as much as 30 kilograms, making it one of the largest and heaviest moray eel species.

When keeping moray eels in home aquariums, it is crucial to consider the specific tank size requirements for large species to ensure their well-being and adequate space.

Species like the green eel and green moray showcase unique colouration and physical adaptations, such as the green moray’s ability to tie its body in knots and its specialised anguilliform swimming technique. Despite their names, green moray eels are rarely green; their appearance is due to a layer of toxic mucus with a yellow hue that covers their bodies, providing protection and facilitating swift movement around the reef. The green reef eel and southern green moray, common inhabitants on temperate rocky reefs on Australia’s east and west coasts, are known for their yellowish to a greenish colour, attributed to a heavy coating of greenish mucous, and their behaviour of poking their heads from holes and crevices with jaws agape.

The size of the moray eel is a determining factor in the level of danger posed to humans, as they do not possess venomous bites. This diversity in size, behavior, and habitat among moray eel species, from the formidable giant moray to the visually striking green moray eels, highlights the rich variety within this fascinating family of marine creatures.

Dragon Moray Eels

Dragon moray eels, also known as Echidna nebulosa, pose a hazard due to their sharp teeth and aggressive behaviour when provoked. They are primarily active during the night, which can present a heightened risk of unexpected encounters.

It has been speculated that dragon moray eels may possess toxins in their mouths, thereby potentially increasing the danger of their bites.

Ribbon Moray Eels

Ribbon moray eels are typically found in tropical and subtropical waters and are known for their long and slender physique and distinctive ribbon-like pattern along their bodies. Although they are not poisonous, they may bite if they feel threatened.

To avoid being bitten by a ribbon moray eel, it is advisable to avoid swimming near them, and if swimming near them is unavoidable, do so slowly and carefully. Cleanse the wound with soap and water and seek medical attention if bitten.

Preventing Moray Eel Bites

A Moray coming out from under the rocks

To prevent getting bitten by a moray eel, avoid contact with them, swim cautiously around them, and follow interaction guidelines. Deep sea divers, coral reef divers, snorkelers and surfers are more prone to being bitten by moray eels. They should take extra caution when engaging in such activities.

If you find yourself in close proximity to a moray eel, the most prudent course of action would be to create a safe distance between you and the eel and avoid making any sudden movements that may startle them.

Safe Swimming Practices

In order to deter mouse eel bites while swimming, it is essential to remain composed and abstain from any abrupt movements that could agitate the eel. Additionally, avoid touching or irritating the eel and be aware of their presence in the vicinity.

Refrain from swimming or snorkelling too close to rocks or crevices where they may be hiding, as their bites can be extremely painful.

Interaction Guidelines

Suppose you encounter a moray eel while diving; it is advisable to adhere to a few simple rules to guarantee a safe and enjoyable experience for all parties involved. First, do not provoke the eel in any manner, as they may respond with an attack.

Second, abstain from providing the eel with sustenance, as this may encourage them to associate humans with food and increase the likelihood of bites.

Moray Eel Bite Treatment

If bitten by a moray eel, it is imperative to act quickly by cleaning the wounds, applying a sterile dressing, and seeking immediate medical attention in order to avert infection.

Moray eel bites can lead to complications such as infection, swelling or difficulty breathing, loss of limb function, surgical removal of adjacent body parts, and septicemia.

Immediate Response

Are eels dangerous?

In the event of a moray eel bite, clean the wound, stop the bleeding, remove any broken teeth from the wound, wash the affected area with soap and water, and apply antibiotic ointment. Apply pressure to the wound with a sterile dressing or a clean cloth to stop the bleeding.

In the case of a deep bite, prompt medical attention may be necessary. Should symptoms of anaphylactic shock arise, please dial 911.

Medical Treatment

The optimal medical treatment for a moray eel bite necessitates aggressive, local wound care and antibiotic coverage that targets Vibrio and Pseudomonas.

If the bite is deep and seriously damages bone or tissue, it may be necessary to surgically remove adjacent parts of the body or severely injured fingers, toes, or other limbs.

Comparing Moray Eels to Other Dangerous Fish

A red lionfish

When comparing moray eels to other dangerous fish species, it is important to note that puffer fish is the most poisonous, red lionfish are venomous, great white sharks are predators, and tigerfish have sharp teeth. Each of these species poses a unique threat to humans, but all should be treated with caution and respect as they can be considered among the most dangerous fish.

Moray eels produce mucus at a higher rate compared to other eel species, and their mucus composition varies significantly, showcasing unique protective characteristics.

Puffer Fish

Puffer fish are the most toxic of all the hazardous fish in comparison to moray eels. They are dangerous due to the presence of tetrodotoxin, a highly toxic substance to humans, which can lead to paralysis and death if ingested. It is estimated that one pufferfish carries enough toxin to be lethal to 30 adults.

Pufferfish are typically found in tropical and subtropical areas, making Indonesia an ideal destination for diving with these creatures rather than observing them in a fish tank.

Red Lionfish

Red lionfish are native to the South Pacific Reef ecosystem and possess a venomous spine, which can inflict a painful sting upon contact. They typically consume fish and shrimp.

When diving with lionfish, visiting the Caribbean and implementing safety measures such as wearing protective gear is essential.

Great White Shark

Great white sharks

The great white shark is a widely recognized and formidable predator. It has been observed that the great white shark usually only inflicts a single bite on its victim when it attacks. After this, it tends to retreat.

Neptune Islands in Australia, Gansbaai in South Africa, Isla Guadelupe in Mexico, Stewart Island in New Zealand, and Tiger Beach in the Bahamas are some of the best destinations to dive with great white sharks. Exploring these locations is an incredible experience that should not be missed!

Moray Eel Behavior and Aggression

Moray eels are typically not aggressive towards humans. However, should they feel threatened or provoked, their behaviour can become dangerous. They live in coral reefs and rocky areas, including notable locations like Shark Bay, Western Australia, where the Sydney Green Eel, a common name for the Green Moray, is found. Moray eels live in warm, saltwater habitats of coral reefs. These habitats provide perfect hideouts for their ambush-based hunting tactics. Most moray eels are nocturnal species, being mostly active during the night time and less so during the day, when they tend to hide in holes and crevices. They mainly feed on fish, crabs, shrimp, octopuses, and squid.

Understanding their behaviour and aggression can help prevent unwanted encounters and bites. In subtropical seas, the hunting techniques of moray eels contrast with those of group

Threatened or Provoked

Moray eels are not usually aggressive; however, they may respond with a moray eel attack when they sense a threat or are provoked. They may employ a defensive strategy in such situations by swiftly biting any perceived hazard.

Feeding and Hunting Habits

A moray eel  and shrimp


Moray eels are nocturnal hunters that slither through the reef during the night hours and corner their prey within reef holes. They are opportunistic predators and feed mostly on smaller fish, crabs, and octopuses. Knowing how to handle moray eels is essential for divers and marine enthusiasts who encounter these fascinating creatures.


Being aware of their feeding and hunting habits can help you avoid unexpected encounters and minimize the risk of bites.


In conclusion, moray eels can be dangerous to humans, but only if threatened or provoked. By understanding their behaviour, following safe swimming practices, and adhering to interaction guidelines, you can minimize the risk of bites and ensure a safe and enjoyable experience in the water. So, the next time you find yourself swimming alongside these fascinating creatures, remember to treat them with caution and respect.


Can eels attack humans?


Although eels can attack humans, it is rare for them to do so. They usually only attack if they are provoked or feel threatened.


It is important to be aware of the potential danger an eel may pose and take precautions when near them.


What happens if an eel bites you?


If you get bitten by a moray eel, it is important to seek medical attention as soon as possible. The bite can cause serious bleeding, swelling, and even infection, which can lead to paralysis in some cases.


Taking immediate action, such as washing the wound with soap and water, is necessary for proper treatment and prevention of complications.


How are eels harmful?


Eels are harmful in multiple ways, including having strong jaws and sharp teeth, which they can use to cause wounds when disturbed, containing toxins that can destroy red blood cells, and producing a poison in their blood serum which has been studied for its effects on humans.


As such, it is important to approach eels with caution.


Are eels dangerous to touch?


Overall, it is generally best to avoid touching eels as they can be dangerous. While some people may handle them safely, even the moray eel and lamprey, which are eaten as food, can react aggressively towards human contact.


Therefore, it is important to remember not to confuse contact with divers as a friendly act, as eels often rub themselves to eliminate parasites from their skin. Ultimately, it is best to avoid touching eels to protect both yourself and the eel.


Will a moray eel attack a human?


Given the potential for serious injury, it is wise to be cautious around moray eels. While they typically won't attack a human unprovoked, they are capable of doing so and should not be approached or handled without extreme caution. As such, it is advisable to keep your distance when encountering a moray eel in its natural habitat.


In conclusion, given their sharp teeth and propensity for attacking humans when disturbed, it is advisable to exercise caution when approaching a moray eel and take steps to avoid spending too much time near known eel habitats. 

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