Are Eels Dangerous to Humans?

Most eels are shy animals that spend their days tucked into rocks and crevices, and they have no interest in people. But “eel” covers some very different animals, and the risk depends on which one you meet and whether you’re touching it, feeding it or eating it. For most people, the realistic dangers are a bite during a close encounter underwater and a few hazards on the dinner plate, not an unprovoked attack.

Which Eels Can Hurt You and How

True eels, including morays, congers and freshwater eels, belong to one group of long, finned fish.1Ocean Conservancy. The Difference Between Electric Eels and True Eels The electric eel is the odd one out. It’s a knifefish, more closely related to carp and catfish than to true eels.2Ocean Conservancy. The Difference Between Electric Eels and True Eels

Where you might meet each one differs. Morays live on warm reefs, where snorkelers and divers spot them in holes. Congers prefer cooler coastal waters such as the North Atlantic, around wrecks and rocks. Electric eels live in South American rivers and in some public aquariums. Freshwater eels mostly matter as food, in sushi or smoked eel.

Morays look scarier than they are. The constant opening and closing of the mouth is how they breathe, not a threat display, and when approached slowly, a moray usually retreats into its hole.

Why Moray and Conger Eels Bite

People usually create the risky encounter. Most moray injuries happen when divers put their hands into holes where eels live or carry freshly cut fish into the water.8Wilderness & Environmental Medicine. Severe Moray Eel Bite Injury: A Case Report and Review of the Literature Because morays hunt largely by smell, an excited eel can grab a hand or a piece of gear during feeding.9abyss.com.au. Moray Eel: Are They Dangerous to Scuba Divers? Moving close for a photo, surrounding an eel or blocking its hole can turn watching into a defensive bite.10abyss.com.au. Moray Eel: Are They Dangerous to Scuba Divers?

A hole is a bad place for a hand. A moray in its home has nowhere to retreat, so a hand pushed in at the entrance looks like a threat or a meal.

Feeding makes things worse over time. An eel fed by hand learns that people mean food, so it may approach every diver, including ones who bring nothing.11abyss.com.au. Moray Eel: Are They Dangerous to Scuba Divers?

Bites aren’t only provoked, though. There is no reliable count of moray bites worldwide, so “they only bite when provoked” goes too far.12Abyss Scuba Diving. Moray Eel: Are They Dangerous to Scuba Divers? In one well-known case, a conger over six feet long bit an experienced diver’s face off Ireland without warning.13LoneSwimmer. Conger eel attack on Irish diver It shook him “like a rag doll” and knocked the breathing regulator from his mouth.14CBC News. Irish scuba diver survives eel bite to the face A bite underwater can add a drowning risk on top of the wound.

A few habits cut the odds. Never reach into crevices or under ledges you can’t see into. Skip feeding, even where guides do it. Keep caught fish and bait sealed or away from your body. Give an eel’s hole space and never block its exit. And keep a backup air source handy in case your regulator is knocked loose.

If an eel does grab you, pulling away hard can make the tear worse, because the teeth angle backward. Keep your breathing equipment in place and stay calm. Once the eel lets go, ascend safely and get help.

What a Moray Bite Does and How It’s Treated

Bites can do more damage than they first look. Moray jaws can cause punctures, deep cuts, crushing injury and heavy bleeding.15Abyss Scuba Diving. Moray Eel: Are They Dangerous to Scuba Divers? Bites to hands and feet are known for damaging tendons and nerves.16All Stings Considered. First Aid for MORAY EEL BITES Broken-off teeth can stay buried in the wound, even in bone, and cause infection if not removed.17Wilderness & Environmental Medicine. Severe Moray Eel Attack: A Case Report and Review of the Literature

Hands and feet carry tendons and nerves close to the skin, so a bite there can injure them even when the wound looks small. Damage inside may not show at first, which is why a hospital checks movement and feeling in the fingers or toes.

Infection is the main later risk. Moray bites can cause serious bacterial infections.18Journal of Venomous Animals and Toxins including Tropical Diseases. Bite by moray eel The germs can come from seawater, the eel’s mouth or your own skin.19PubMed. Emergency Management Strategies and Antimicrobial Considerations for Nonmammalian Marine Vertebrate Penetrating Trauma in North America, the Caribbean, and Hawaii: A Review Article The main germs in moray mouths include Vibrio and Pseudomonas, names you may hear from your doctor.20PubMed. The emergency management of moray eel bites So after cleaning the wound, doctors usually give antibiotics chosen to cover Vibrio.21PubMed. Emergency Management Strategies and Antimicrobial Considerations for Nonmammalian Marine Vertebrate Penetrating Trauma in North America, the Caribbean, and Hawaii: A Review Article Once germs are driven deep into a puncture, the surface can look fine while an infection builds underneath, which is why early cleaning counts.

In the field, press firmly on the wound to stop the bleeding.22Wilderness & Environmental Medicine. Severe Moray Eel Attack: A Case Report and Review of the Literature For minor bites, gently open the skin edges and rinse, or use tweezers to remove teeth.23All Stings Considered. First Aid for MORAY EEL BITES Then scrub inside the bite with a clean cloth soaked in clean fresh water, which doesn’t add more seawater germs.24All Stings Considered. First Aid for MORAY EEL BITES Get every eel bite checked at a hospital, including your tetanus status.25Wilderness & Environmental Medicine. Severe Moray Eel Attack: A Case Report and Review of the Literature

At the hospital, X-rays can show teeth hidden in the wound.26Wilderness & Environmental Medicine. Severe Moray Eel Attack: A Case Report and Review of the Literature Deeper bites may need cleaning in an operating room and checks of tendons, vessels and nerves.27Wilderness & Environmental Medicine. Severe Moray Eel Attack: A Case Report and Review of the Literature You’ll get a tetanus shot if your vaccination is unclear or out of date.28Wilderness & Environmental Medicine. Severe Moray Eel Attack: A Case Report and Review of the Literature Even with antibiotics, any early sign of infection needs prompt treatment.29Wilderness & Environmental Medicine. Severe Moray Eel Attack: A Case Report and Review of the Literature

In the following days, watch for spreading redness, warmth or swelling around the bite, and for pus, increasing pain or a foul smell. Fever or red streaks moving up the limb are warning signs too. Trouble moving your fingers may mean tendon damage.

How Dangerous Electric Eel Shocks Are

An electric eel shock is a rapid burst of high-voltage pulses lasting from a tenth of a second to 20 seconds.30PubMed Central. Two Clinical Records of Human Injuries with a Death caused by Electric Eels Electrophorus spp. Gill, 1864 The pulses force muscles to contract involuntarily, so they paralyze the target.31PubMed Central. Two Clinical Records of Human Injuries with a Death caused by Electric Eels Electrophorus spp. Gill, 1864 When defending itself, an eel fires several bursts in a row.32PubMed Central. Two Clinical Records of Human Injuries with a Death caused by Electric Eels Electrophorus spp. Gill, 1864 A record of human injuries from electric eels includes a death.33PubMed Central. Two Clinical Records of Human Injuries with a Death caused by Electric Eels Electrophorus spp. Gill, 1864 The eel can fire again right after the first burst, so pulling away quickly matters more than waiting to see what happens.

Leaping makes shocks stronger. A threatened eel can leap out of the water and press its chin against the threat while discharging.34PubMed Central. Leaping eels electrify threats, supporting Humboldt’s account of a battle with horses That sends the current through the threat, and the higher the eel climbs, the more power reaches it.35PubMed Central. Leaping eels electrify threats, supporting Humboldt’s account of a battle with horses The behavior produces a painful, deterring jolt.36PubMed Central. Electrical Potential of Leaping Eels A person standing in a river or at a tank edge can be reached, so being out of the water doesn’t make anyone completely safe. The leap is a defense against something large, so it’s most likely when an eel is cornered, grabbed or chased.

Even a small eel sent current through a person’s arm far above the level that triggers pain.37PubMed. Power Transfer to a Human during an Electric Eel’s Shocking Leap But in that test, the pain stayed in the touched arm, without full-body muscle locking.38PubMed. Power Transfer to a Human during an Electric Eel’s Shocking Leap That’s reassuring only for one situation: larger eels, repeated bursts and standing in water change the picture.

Water adds its own danger. Being stunned in water can make a person fall and drown, and repeated bursts can keep muscles locked while you try to escape.

Never touch or net one, in the wild or in a tank. Aquarium keepers count electric eels among dangerous species alongside lionfish.39BSAVA Library. Health and safety Turn off and drain equipment before maintenance, and use insulated tools.

Is Eel Safe to Eat

Eel blood is poisonous to humans and other mammals.40Wikipedia. Eel as food It contains a toxic protein that has killed mice when injected.41PubMed. Purification and characterization of a proteinaceous toxin from the Serum of Japanese eel Anguilla japonica Cooking and digestion destroy that protein, though.42Wikipedia. Eel as food That’s why properly cooked eel dishes, including grilled eel in sushi, are widely eaten and safe from this toxin, while raw preparations that include blood are a different matter. A cut hand touching raw blood can also be a route in.

Moray meat carries a different problem. Ciguatera is food poisoning from a toxin made by tiny reef organisms that builds up in fish that eat other reef fish. Moray eels can carry very high levels in their flesh and especially the liver.43PubMed Central. Regional Variations in the Risk and Severity of Ciguatera Caused by Eating Moray Eels Even a small moray can be toxic, and one normal portion, especially of liver, can cause severe or fatal poisoning.44PubMed Central. Regional Variations in the Risk and Severity of Ciguatera Caused by Eating Moray Eels In one outbreak in Vietnam, the toxin was in the meat but not the skin.45PubMed Central. Pacific Ciguatoxin-1 (P-CTX-1) in a Moray eel (Gymnothorax javanicus) Responsible for Ciguatera in Khanh Hoa Province, Viet Nam

Cooking or freezing does not destroy ciguatera toxin. It has no taste or smell, so a toxic moray looks and tastes like a safe fish.

Ciguatera fish poisoning starts with nausea, vomiting and diarrhea within hours of eating. Lips and hands tingle. Cold can feel hot, a strange reversal that is a hallmark of the illness. Nerve symptoms can last weeks.

If you suspect it, tell medical staff exactly what fish you ate and where, since ciguatera fish poisoning can be mistaken for ordinary food poisoning. Warn anyone who ate from the same fish, because they may be affected even if symptoms haven’t started.

Is Eel Slime Poisonous

Moray mucus contains several toxic substances, including one that clumps red blood cells and one that destroys them.46WetWebMedia. Moray eels bite – But are they poisonous? Special cells in the skin produce these toxins rather than the eel getting them from food.47WetWebMedia. Moray eels bite – But are they poisonous? Handling morays bare-handed or with cuts is best avoided.

Still, morays don’t inject venom like a snake. The mucus toxins mainly protect the eel’s skin, and bite pain and infection are the bigger medical concern. The risk is greatest where mucus reaches broken skin. Slime on unbroken skin isn’t known to cause serious harm, but the eel may bite, so anglers should use gloves when unhooking one.

After contact, wash your hands and any skin that touched the eel with clean water and soap. If slime gets into a cut, clean it thoroughly and have it looked at, especially if redness or pain develops.