…the secret life of eels

It’s a bright, warm day and you’re snorkelling near shore when you see what looks like a spotted snake in a bed of seagrass.  On the nearby sand flat, a group of brown worms are standing up and swaying with the current – until they see your shadow and disappear without a trace.  Poking out of a hole in the rocks, there’s a fish with a long nose, mean little eyes and an open mouth full of sharp teeth... These are all eels.

Their bodies are long and round, with no side fins.  Their skin has no scales, and is covered with a coat of slime that protects them from scratches.  Their dorsal (top) and anal (bottom) fins run the length of their bodies, meeting in a slightly rounded tail.  They eat almost anything smaller than they are, including other eels, and they’re happy to clean up bits of dead stuff from the sea floor.

The snake eels – both the flashy Goldspotted and its plainer Sharptail cousin – are active in the daytime, looking for food on sand bottoms and seagrass beds.  The little Brown Garden Eels stand up over their holes in a mud or sand flat and wait for the current to bring dinner.

Moray eels are very shy, and a lot harder to find.  During the day, they spend most of their time in holes in the reef, in caves or under ledges.  Because the moray does more open-water swimming than snake and garden eels, its fins are bigger in proportion to its body.  The larger fins also help to anchor the moray in its hole.

A moray with its mouth open looks threatening, but it’s just breathing.  Morays have to open and close their mouths to move water over their gills, because their small gill openings are set a lot further back from their heads than most fish and have no covers to pump water.

Morays can’t see or hear very well, but they have a very sharp sense of smell.  If something edible passes near a moray’s den during the day, the moray may dart out and grab it, but mostly they hunt at night.  The darkness is no handicap to their good noses, and shelters them from ambush by the barracudas, groupers and other large fish that eat them.

The moray has a mouthful of sharp, backward-pointing teeth and a secret weapon – a second set of jaws with teeth, stored at the back of its throat.  When the moray grabs something big, these jaws swing forward into its mouth, then swing back to pull the prey in.

Morays have a reputation for being dangerous to people.  They will sometimes go after speared or hooked fish, and because of their poor eyesight they get the fisherman instead.  They will also bite the hands of people that poke into their dens, and trying to feed them is a bad idea – they really can’t see where the fingers stop and the food begins.

A moray bite is dangerous.  Because the teeth point backwards, it’s hard for the moray to let go even if it wants to, and those teeth are covered with bacteria that can cause serious infection.  If you see a snake eel, garden eels or a moray, enjoy them and leave them alone.  Like the rest of us, these useful, beautiful and interesting creatures just want a little respect.