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Slowly descending, I looked below and could see a picturesque bottom topography of corals and sand. There were colourful reef fishes everywhere, yet what caught my eye was a black and white banded sea snake weaving across the bottom. I headed straight for the snake, or what I thought was a snake, as when I got closer, I realised it was an imposter, a Banded Snake Eel!

This got me even more excited as it was the first tropical snake eel I have ever encountered, and I was even more surprised to see one out by day. As I watched, the eel slowly moving across the bottom poking its head into every nook and cranny, possibly looking for small fish and crustaceans to eat. It didn’t seem to have a worry in the world, as all the other fish ignored it or moved out of its way. It had fooled me into thinking it was a venomous sea snake, so I assumed it was also working on the fishes. I followed it for a few minutes until it tired of my company and dug itself into the sand, tail first and completely disappeared.

That encounter, almost forty years ago, got me fascinated by snake eels. In the years since I have attempted to learn as much as I can about them and seek out these strange and elusive eels of the sand every chance I get.

Snake eels are members of the family Ophichthidae, and are named for their snake-like appearance, having a rounded body. While some look like morays and conger eels, snake eels generally have small teeth, large eyes, small fins and a pointed tail, that helps them quickly bury in the sand tail-first.

Snake eels vary greatly in size and shape, with the smallest only 5cm long and biggest close to 3m long. Within the family there are 62 genera and over 320 species. They are found in both tropical and temperate waters in oceans around the world. These eels mainly live in sandy areas in shallow seas, however some live in depths to 800m. Most are bottom dwellers, living in the sand by day and stalking prey by night. However, there are also a few pelagic species that roam the open ocean. Some snake eels have plain colours that help them to camouflage with the sand or mud of their home, while others have bright colours, spots and bands.

IMAGE BELOW - BANDED SNAKE EEL

Most snake eels are nocturnal, only leaving their hiding spot in the sand at night to search for small fish, cephalopods and crustaceans. However, some don’t even do that and instead only have their head exposed at night and ambush prey that gets within striking range. By day all you see of most snake eels is their head poking out of the sand. However, some snake eels hide completely in the sand by day and don’t even expose their head.

The most interesting snake eels are the ones that mimic sea snakes. They have the same black and white banded patterns of several sea kraits, which allows them to boldly roam the sand and rubble by day searching for prey without being eaten or harassed by predatory fish. However, it doesn’t stop them being eaten by moray eels or the sea snakes they mimic.

Little is known about the biology and behaviour of snake eels. Snake eels are not very social like some other eel families. You never find snake eels sharing a hole in the sand, and never see them hunting together. They occasionally have holes close together but are usually a few metres apart. About the only time they come together is to breed.

Mating between snake eels has been rarely documented. When it has been observed it has generally been over summer and around dusk. There may be foreplay involved and males establishing dominance, but this is largely unknown. What has been observed is the male and female leaving their hiding spots, intertwining their bodies and releasing their eggs and sperm into the water column. The young then drift with plankton until they are large enough to burrow into the sand.

One of the most interesting behaviours of snake eels is their ability to dig into the sand backwards. To do this they have a hard pointed tail, and it is amazing how quickly they can accomplish this feat, literally in seconds. Recently scientists discovered another bizarre use for this hard pointed tail, when they found that snake eels use it to burst through the stomach of predatory fish!

Jeff Johnson, an ichthyologist with the Queensland Museum, found that if the snake eel was swallowed whole by the fish, it could burrow through the stomach wall. Unfortunately, this didn’t result in the snake eel escaping as they couldn’t penetrate the outer wall of the gut cavity. In a study Jeff found seven species of snake eels in the stomachs of eleven fish species. The escape process didn’t kill the fish, but the poor snake eels eventually died and became preserved in the gut cavity.

‍IMAGE BELOW - YELLOW-LIPPED SEA KRAIT, THE BANDED SNAKE EEL MIMICS THIS SEA SNAKE

SNAKE EEL SPECIES

While there may be over 320 species of snake eels found around the world, very few are seen by divers. Around 50 species are found around Australia. However, I have always found the muck sites of Indonesia and the Philippines the best place to find snake eels. The following snake eels are the most common ones that divers can see in Australia and Southeast Asia. However, I have also included a few rarer species I have photographed over the years.

BANDED SNAKE EEL (Myrichthys colubrinus)

This is one of the most wide-ranging and common snake eels that divers see throughout the Indo-Pacific region. The Banded Snake Eel grows to 1m in length and is white with black bands. This species is mostly seen out in the open in the early morning or late afternoon, though you will still see the odd one out in the middle of the day. I have encountered this species throughout Southeast Asia and in tropical and subtropical regions of Australia, with the sheltered sandy bays at Norfolk Island a great place to see several each day.

CONVICT SNAKE EEL (Leiuranus versicolor)

This eel looks almost identical to the Banded Snake Eel, as it also has a black and white banded pattern. However, you can tell them apart as their black bands have a white spot on them. The Convict Snake Eel grows to 76cm in length and is also a mimic of sea snakes, so are often seen roaming about by day. They are far rarer than their cousin and only occasionally seen in Southeast Asia and northern Australia. The only place I have seen a Convict Snake Eel is in Emily Bay at Norfolk Island.

IMAGE BELOW - CONVICT SNAKE EEL

NAPOLEON SNAKE EEL (Ophichthus bonaparti)

One of the most colourful members of the family is the pretty Napolean Snake Eel. This species grows to 75cm long and has a creamy coloured body with brown blotches on the face and brown bands along its body. Found throughout Southeast Asia, the Napolean Snake Eel is quite common at muck sites, having its pretty head exposed by day. As it also has a banded body, this species occasional roams the sand by day, but are quick to rebury if a diver gets too close.

‍IMAGE BELOW - NAPOLEON SNAKE EEL

MARBLED SNAKE EEL (Callechelys marmorata)

This distinctive member of the family has a small snout, wrinkly skin and likes to have its head positioned vertically out of the sand. The Marbled Snake Eel is a white to yellow colour with black spots and blotches decorating its head and body. This species grows to 87cm in length and is found throughout the Indo-Pacific region, including northern Australia. The Marbled Snake Eel is another species that is common at muck sites in Southeast Asia, and often seen by day with its head proud of the sand.

‍IMAGE BELOW - MARBLED SNAKE EEL

BLACKFIN SNAKE EEL (Ophichthus altipennis)

This is another snake eel that likes to poke its head vertically out of the sand. The Blackfin Snake Eel grows to 1m in length and is a yellowish to light brown colour with a scattering of darker spots on its head and with distinctive black fins. This is another common snake eel at muck sites in Southeast Asia, and the tropical waters of Australia. However, it is also seen off Perth for some reason. At muck sites in Indonesia, Blackfin Snake Eels are sometimes seen with commensal shrimps sitting on their head.

IMAGE BELOW - BLACKFIN SNAKE EEL

CROCODILE SNAKE EEL (Brachysomophis crocodilinus)

With beady eyes and visible teeth, the unattractive face of the Crocodile Snake Eel always reminds me of a skull grinning from the sand. This species grows to 80cm long, has a small head and is a cream white colour with irregular small dark spots. The Crocodile Snake Eel is an ambush predator that sits with only its face exposed waiting to catch prey. This species can be hard to find without a good guide, as their face tends to blend with the sand. The Crocodile Snake Eel is found at muck sites in Southeast Asia. It is reported to be found in Australia as well, but the only place in Australia where I have seen one is Christmas Island.

IMAGE BELOW - CROCODILE SNAKE EEL

REPTILIAN SNAKE EEL (Brachysomophis henshawi)

The Reptilian Snake Eel is one of the most impressive members of this family with its red colouration and prickly skin. This strange looking snake eel grows to 1m in length and is mostly seen in Southeast Asia. They are generally seen at night, being ambush predators, but I have seen the occasional head protruding from the sand by day.

IMAGE BELOW - REPTILIAN SNAKE EEL

MANY-EYED SNAKE EEL (Ophichthus polyophthalmus)

The prettiest snake eel I have ever seen is the Many-eyed Snake Eel. This rarely seen eel is found throughout Southeast Asia and grows to 62cm long. This attractive eel has an orange snout, and a greyish-white body with a covering of yellow spots. I have only seen one of these elusive snake eels on a dive of Padang Bai, Bali.

IMAGE BELOW - MANY-EYED SNAKE EEL

SERPENT SNAKE EEL (Ophisurus serpens)

This temperate snake eel is one of the longest, growing to 2.5m long. The Serpent Snake Eel has an elongated, pointy snout and small sharp teeth. It is a sandy colour that helps it blend into the sand. By day, divers sometimes see the head of this eel, however, they are more commonly seen at night when they protrude from the sand while trying to catch prey. This wide-ranging eel is found off southern Australia, northern New Zealand and strangely also in the Mediterranean. I have seen them in Port Stephens and at a few sites around Sydney.

IMAGE BELOW - SERPENT SNAKE EEL

LONGFINNED WORM EEL (Scolecenchelys breviceps)

Worm eels are contained within the snake eel family, but are much smaller and thinner, some would even say worm-like. The Longfinned Worm Eel is only found in southern Australia and New Zealand but is rarely seen. They are a pale yellow to green colour on top with a white belly and grow to 60cm long. Longfinned Worm Eels are mostly seen at night, when they emerge to hunt prey, and divers have seen them on shore night dives off Melbourne, Adelaide and Perth. The only one I have seen was out in the day, briefly, at Busselton Jetty. It popped out of the seaweed for a second and just as quickly disappeared.

I have many more snake eel species left to find and photograph that will keep me happily hunting the sand for these elusive eels for many years to come.

IMAGE BELOW - LONGFINNED WORM EEL