# Moray Eel (*Muraenidae*)

> Moray eels are a family of long, snake-like marine fish (Muraenidae) found in coral reefs and rocky crevices, mostly in warm and temperate seas. They swim with an undulating, ribbon-like motion and shelter in holes by day, striking out to catch fish, crustaceans, and octopuses. Large species can reach 3 m (10 ft) and around 15 kg, and many live 10 to 30 years depending on the species.

- **Category:** Fish
- **Conservation status (IUCN):** Least Concern
- **Range:** Coral reefs and rocky crevices in tropical and temperate seas worldwide.
- **Canonical page:** https://globalanimalguide.org/animals/moray-eel/
- **Last reviewed:** 2026-07-16

## Scientific classification

- **Kingdom:** Animalia
- **Phylum:** Chordata
- **Class:** Actinopterygii
- **Order:** Anguilliformes
- **Family:** Muraenidae

## Facts at a glance

| Attribute | Value |
| --- | --- |
| Scientific name | Muraenidae |
| Diet | Carnivore (fish, crustaceans, cephalopods) |
| Habitat | Coral reefs and rocky crevices |
| Lifespan | 10–30 years by species |
| Length | Varies; up to 3 m (10 ft) in large species |
| Top speed | Fast strike from cover |
| Conservation status | Varies by species |

## Appearance and body plan

Morays have a slender, muscular, snake-like body with no pelvic or pectoral fins, and a long dorsal fin that runs the length of the back. Their scaleless skin is covered in a protective mucus, and many species are patterned to blend into reef crevices. Size varies widely between species, with large ones reaching up to 3 m (10 ft) and weighing around 15 kg. Their constantly open mouth, showing rows of needle-like teeth, is a breathing action rather than a threat.

## The hidden second jaw

One of the moray's most remarkable features is a second set of jaws, called pharyngeal jaws, hidden in the throat. When the eel seizes prey with its outer jaws, this inner set surges forward into the mouth, grips the prey, and drags it back toward the gut. This adaptation lets morays swallow struggling prey in the tight confines of a reef crevice, where they cannot create suction the way many open-water fish do. Few other animals are known to feed in this way.

## Habitat and behaviour

Moray eels live in coral reefs, rocky reefs, and crevices, mostly in tropical and subtropical seas, with some species in temperate waters. By day they usually shelter in holes with only the head protruding, and they become more active hunters at night. Although they can strike quickly from cover, they generally swim slowly and stay close to their den. Their apparent gaping is simply how they pump water over their gills to breathe.

## Diet and hunting

Morays are carnivores that feed on fish, crustaceans, and cephalopods such as octopuses. They hunt largely by ambush, waiting in a crevice and lunging out with a fast strike when prey passes, relying on a keen sense of smell to locate food in dim conditions. Some species have been observed cooperating with reef fish such as groupers, which flush prey out of hiding for the eel to catch. Their backward-pointing teeth make it very hard for prey to escape once seized.

## Reproduction and lifespan

Most morays release eggs and sperm into open water, where fertilised eggs develop into transparent, leaf-shaped larvae that drift with the plankton before settling onto a reef. This larval stage can last for months, helping the young disperse over wide areas. Depending on the species, morays live roughly 10 to 30 years. They grow slowly and can occupy the same crevice for long periods once established.

## Frequently asked questions

### Are moray eels dangerous to humans?

Moray eels are not naturally aggressive toward people and prefer to stay hidden in their crevices. Bites usually happen when a diver reaches into a hole or tries to feed them, and their sharp, backward-facing teeth can cause a serious wound.

### Why do moray eels keep their mouths open?

The constant opening and closing of a moray's mouth is how it pumps water over its gills to breathe, not a sign of aggression. Because they rest in tight crevices, this pumping is more visible than in fish that swim in the open.

### How big do moray eels get?

Size varies greatly by species, from under a metre to about 3 m (10 ft) in the largest. Big species can weigh around 15 kg, with a long, muscular body built for life in reef crevices.

### What do moray eels eat?

Morays are carnivores that eat fish, crustaceans, and cephalopods such as octopuses. They ambush prey from cover and use a hidden second set of jaws in the throat to pull food back and swallow it.

### How long do moray eels live?

Lifespan depends on the species, but many morays live between 10 and 30 years. They grow slowly and may hold the same den site for years once settled.

### Do moray eels really have two sets of jaws?

Yes. In addition to their outer jaws, morays have pharyngeal jaws in the throat that shoot forward to grip prey and drag it toward the stomach. This lets them swallow prey inside narrow crevices where suction feeding is not possible.

## Sources

- [IUCN Red List — Muraenidae.](https://www.iucnredlist.org/search?query=Muraenidae&searchType=species)
- [Wikipedia — Moray Eel.](https://en.wikipedia.org/wiki/Moray_eel)

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Source: Global Animal Guide (https://globalanimalguide.org/animals/moray-eel/). Licensed CC BY-NC 4.0 — free for non-commercial reuse with attribution.