Giant Moray

The giant moray (Gymnothorax javanicus) is a species of moray eel and marine fish in the family Muraenidae. It holds the distinction of being the largest moray eel in terms of body mass, although the slender giant moray is longer in body length.

Measuring up to 3 m (9.8 ft) in length and weighing around 30 kg (66 lb), the giant moray lives up to its name. Its elongated body is typically brownish in color. Juveniles display a tan color with prominent black spots, while adults possess black specks transitioning into leopard-like spots behind the head.

This species can be found in the Indo-Pacific region, ranging from the eastern coast of Africa (including the 🌊 Red Sea) to the Pitcairn group, Hawaiian Islands, and Polynesia. It is also present in 🇯🇵 Japan's northern to southern regions, extending to 🇳🇨 New Caledonia (🇫🇷 Overseas France), 🇫🇯 Fiji, and the Austral Islands (🇵🇫 French Polynesia). The giant moray typically inhabits lagoons and the outer slopes of coral reefs, seeking shelter in crevices at depths ranging from 1 to 50 meters during the day.

As a carnivorous and nocturnal species, the giant moray hunts within the reef. It is known to engage in cooperative hunting with the roving coral grouper (Plectropomus pessuliferus). Acting as complementary hunters, the eel scares prey out of the reef while the grouper waits to consume them. In a similar manner, the grouper's hunting may drive prey into the reef, where the moray lies in ambush.

The giant moray's diet primarily consists of fish, with occasional consumption of crustaceans. Recently, it has been discovered that this moray eel serves as a natural predator of lionfish (Pterois miles) in its native habitat in the 🌊 Red Sea. While few natural predators pose a threat to mature giant morays, competition for food may occur with reef-dwelling sharks. Cleaner wrasses are commonly observed cleaning the interior of their mouth.

It is worth mentioning that Gymnothorax javanicus exhibits very small optic tectum volumes, indicating a reliance on smell rather than vision during hunting.

Caution should be exercised around this species as it can pose a threat to humans. Being at the top of the food chain, the giant moray is known to accumulate harmful ciguatera toxins, which can cause illness, coma, or even death if consumed, particularly in the liver. While the moray may bite if threatened, cornered, or near food, it is generally not aggressive.