Underwater Highlights of Lembeh Strait

By any measure, Lembeh Strait in Indonesia is one of the world's great epicenters of weirdness.   This striped frogfish is just one of many examples of the strange critters to be found in this stretch of shoreline between the northern coast of Sulawesi and Lembeh Island.   The frogfish doesn't do much swimming like a regular fish, instead it walks along on the sea floor.   It's an ambush predator, waiting for something tasty to come along, attracted by the lure which you see on top of its head, which is at the end of a little fishing rod which the frogfish twitches around in front of its mouth.

Frogfishes are only the beginning of the strangeness in this place.   This dragon sea moth or little dragonfish also avoids swimming around, instead walking along the bottom in close proximity to its mate.   It has a snout which would make any mother proud and its cryptic coloration makes it blend very well into the background, just in case anything is silly enough to eat such a bony little fish.   When they accumulate too many parasites and other baggage they can shed their whole skin in one move by rapidly leaping forwards.

But the grand prize for camouflage goes to the halimeda ghost pipefish, named for the green leafy halimeda algae it lives amongst.

This fish has not only matched the color of its surroundings, its lobed fins have even taken on the same shape as the leaves of the algae.

They can even change their color to match dead or dying grey leaves and, if you look straight below this green individual then you'll see that its mate is a totally different dull brown hue.

These guys are so cryptic and uncommon that they were only scientifically described as recently as 2002.

This longsnout flathead is a lot bigger than the halimeda ghosts pipefishes and isn't anywhere near as rare, but it's interesting nevertheless.   The different species of flatheads are also called crocodilefishes and, with a shape like this, it's easy to guess that they spend most of their time lying on the sea floor.

Some of the fish in Lembeh Strait won't even settle for lying down on the bottom, they insist on actually digging themselves in!

This is a whitemargin stargazer which swam past me as I was photographing a snake eel on a night dive.

Neither of these two creatures is commonly seen swimming in the open, but it was obvious that when this guy came past it was "goodbye snake eel, hello stargazer", since the stargazer is such an extraordinary looking animal, and much less common than the snake eels.   I had some more luck when it decided to bury itself just a few meters away from where I first saw it.

Stargazers get their name both from being nocturnal and from their habit of looking up, which is pretty much a necessity when the rest of their rather large body is buried in the sand.

Like the anglerfishes, stargazers also have a lure, which you can see just in front of its mouth.

You can see a couple of spines at the broadest part of this fish's back.   Not only are these spines hard and sharp, they're also toxic enough to cause a serious wound in any diver stupid enough to provoke the stargazer.   On top of that, they also have an electric organ which is apparently defensive and can generate around 50 volts.

This oddity is another scorpionfish and yet another fish that prefers walking to swimming!   Because of the powerful venom in their fin spines, scorpionfishes are one of the most feared families of animals in the ocean; this leaf scorpionfish is much smaller than the two Rhinopias species above, but it's actually the only one of the three which is considered dangerous.    However, like all other scorpionfishes it isn't aggressive, in fact it gets its name from its habit of slowly rocking from side to side in the current, pretending that it's a leaf, just like the cockatoo waspfish which looks very similar and also lives here.

Moray eels are another family which induce a lot of fear, but with far less cause than the scorpionfish family.   Although they have large, sharp teeth, you'd have to corner a moray and provoke it pretty badly to make it bite you.   Usually you don't see them out in the open like this, but I found this minor moray eel while on a night dive, when it felt safe enough to venture forth.   This is the first time I've seen this species, but there were also fimbriated, snowflake and white-eyed morays around, as well as a couple of other species I couldn't identify.

Believe it or not, this cute critter is another moray eel, usually called a ribbon eel, but occasionally called a leaf-nosed moray because of the way the ends of its nostrils flare out.

People used to believe that there were three species of ribbon eel, one black, one blue and yellow like this individual, and another which is entirely yellow.

After a lot of investigation it was learned that there is only one species, the black ones being juvenile males, the attractive blue and yellow ones being adult males and the yellow ones being females.   And no, there are no juvenile female ribbon eels, which begs the question:  What the heck???

Here's how it work:   when it grows up the juvenile males change color and become adult males and then, when it's sick of that, the adult male abruptly changes sex and becomes female and yellow!   It's the only moray eel which pulls this sort of trick, though quite a few other fish like the ever popular clownfish do the same thing.   Yes, you heard me right - Nemo's mom was actually a male before Nemo's dad met her and married her!

Ribbon eels aren't that rare per se, but for some reason females are very uncommon, so much so that I've never seen one.

By now you should have noticed that there's a distinct lack of coral and pretty fish at Lembeh.   That's because this is the world capital of muck diving, which is all about diving where the sea floor is composed of sand, gravel or rubble instead of coral reefs.   But amid all of the weirdness there's still plenty of attractive animals like the ribbon eel, and there are even small areas of coral with the usual populations of butterflyfishes and other tropical beauties.   And then there are anemones scattered around with the ever-popular clownfishes and specialties like this Banggai cardinalfish, which was introduced here from the nearby Banggai islands.

There are plenty of other interesting crustaceans here, like this spotted porcelain crab.   It has only three pairs of walking legs and it also has long antennae, which give away the fact that it isn't a true crab, instead it's more closely related to squat lobsters.   It feeds by waving around a pair of feathery structures held near its mouth, using them like baskets to strain plankton out of the water.

When underwater photographers want to find something beautiful, they go looking for slugs!   Sea slugs like this Mexichromis multituberculata have vibrant colors and patterns, and sometimes an interesting shape as well.   This one is even doing a passable imitation of a reindeer - its left rhinopore, the purple structure on the right side of the photo, is branched, which is very unusual and maybe indicates an injury.   This sea slug is doing something else interesting, too - laying eggs!   You can see the flat ribbon of eggs coming out of its side, it'll keep going until it's laid a complete spiral of eggs.

The dive site called Nudi Retreat is famous for another mollusc, commonly called the "electric clam".   It's a brilliant red color with lots of tentacles, but its most extraordinary feature is what looks like rapid pulses of bright light constantly rippling around the edges of its mantle.   It's really something you need to see on video, but this photo does show some of the bright patches in action.