There are around 200 species of Moray Eel in the world's oceans. Despite their snake-like appearance and lack of pectoral and pelvic fins, they are fish, not reptiles. While they are generally shy, sightings are common in Thailand. The most common one you'll encounter while diving in Koh Tao is the white-eyed moray eel.
Distinguishing Features
The White-Eyed Moray Eel stands out with its bright white eyes. It features a purplish-grey head and a body that's pale yellow-brown or whitish with dark speckles. Typically growing to around 40 cm, larger males can reach up to 65 cm.
Behaviour
These eels are carnivorous, feeding primarily on fish, squid, and other crustaceans. An interesting behavior is their rare yet fascinating co-operative hunting! You might see a Grouper surrounding the coral area, creating a barrier that traps smaller fish. As the prey is pushed towards the center, the White-Eyed Moray Eel moves through the gaps to catch any fish trying to escape. This teamwork benefits the moray eel, as the trapped fish are easier to catch, and the other fish - like Grouper - snag any that attempt to flee. In addition to co-operative hunting, White-Eyed Moray Eels are generally shy and prefer to stay hidden in crevices or under rocks. They use their strong jaws and sharp teeth to grasp and subdue prey. Their behavior is adapted to minimize energy expenditure, so instead of constant swimming, they remain mostly stationary, positioning themselves strategically with their mouths open to facilitate water flow over their gills.
Symbiotic Relationship
White-Eyed Moray Eels have a great ally on the coral reef: the cleaner shrimp. These shrimp remove parasites and debris from the eel’s jaws, providing a thorough cleaning. In return, the cleaner shrimp get a free feast of parasites. It’s a win-win arrangement for both!
Eel or Alien?
Just like the monster in Alien, moray eels have a hidden set of toothy jaws! Inside their throat are secondary pharyngeal jaws that assist in capturing prey. Unlike most predatory fish that use suction to swallow, morays use a different approach. First, their outer jaws grab onto their prey with a firm bite. Then, their secondary set of jaws shoots forward, clamps down, and pulls the prey further into their throat. It might sound a bit terrifying, but don’t worry—humans aren’t on their menu!
Breeding
White-Eyed Moray Eels breed by releasing their eggs into open water, where the larvae drift with the currents before settling on reefs to grow into juvenile eels. They aren't the most attentive parents, as many juvenile eels don’t survive for long. However, they lay up to 60,000 eggs at a time to increase the chances of some reaching adulthood.
Where to Find White-Eyed Moray Eels on Koh Tao
White-Eyed Moray Eels are mostly nocturnal, so your best chance to see them in action is during a night dive at White Rock.
However, you can also spot them during the day at various dive sites around Koh Tao that offer plenty of coral or rocks for hiding. Popular spots to catch a glimpse include
Twin Peaks,
Laem Thian,
Chumphon Pinnacle,
Mango Bay,
Japanese Gardens,
(etc..)
Diving in Koh Tao offers numerous opportunities to encounter White-Eyed Moray Eels.
