The Lembeh strait in North Sulawesi, Indonesia offers some of the best muck diving. Muck stands for the muddy or “mucky” sediments which cover most of the dive sites. This type of diving is defined as looking for small stuff in areas without or with just little coral but mainly sediment. Below are 13 of the reasons to dive Lembeh 😉


1) Hairy frog fish

hairy frogfish walking

Frog fish are often grumpy looking bottom-dwellers. Most of the time they sit on the sea floor without moving a lot. They are well camouflaged which protects them from predators and helps them to catch prey. When prey approaches the frog fish opens its mouth widely in a sudden movement that pulls it into its mouth. This movement is also called yawning. The hairy frog fish are not actually hairy but covered in small spines which are part of the camouflage.


2) Lembeh sea dragon

Lembeh sea dragon

Lembeh sea dragons are also called pygmy pipehorses. As the name suggests are these fish related to seahorses and pipefish. The Lembeh sea dragon can only be found in the Lembeh strait and some other areas in Indonesia. They are up to a couple of cm in length with a very thin string-like body. Therefore it is not surprising that they were only discovered in 2006.


3) Pygmy seahorse

pygmy seahorse

I do love all types of sea horses and the tiny pygmies even a little bit more. Is that a girl thing? There are 3 different types of pygmy seahorses to be found in the Lembeh strait. They are hard to spot as they are very well camouflaged and the maximum size is less than 3 cm (about 1 in). They can only be found in Southeast Asia in the so-called coral triangle. Like all sea horses the males carry the fertilized eggs. However, unlike other seahorses they brood their young inside their trunk, instead of in a pouch on the tail.


4) Nudibranchs

nudibranch with passenger

The Lembeh strait is nudibranch heaven. Oh and I do love nudibranchs, those are sea slugs that come in so many colours and forms. Most importantly they don’t move very fast which makes them a perfect subject for underwater photography 😉 The name nudibranch stands for naked gill which is appropriate as they breathe through a branchial plume that forms a cluster on the back of its body. They are hermaphroditic carrying female and male reproductive organs.


5) Bobtail squid

bobtail squid

These very small, very colourful squid bury themselves in the sand so as not to be found by scuba divers and predators. They are closely related to the cuttlefish and are mostly to be seen during night dives. The bobtail squid live in a symbiosis with bioluminescent bacteria that inhabit its mantel. The bacteria provide camouflage by imitating the night sky so the squid cannot be seen easily from below while the bacteria are fed by the squid.


6) Coconut Octopus

coconut octopus

They mostly live on the sandy bottom. If you give them a coconut they will hide in it. If there is no coconut they will take whatever they find like an empty bottle or shells. If they do not find shelter they will bury themselves in the sand so only the eyes stick out. We’d been watching this coconut octopus for about 10 minutes as he tried to build a “house” with a coconut and two shells. Somehow he did not seem happy with the set-up, so he tried with only one shell but there wasn’t enough room in it for him to hide.


7) Mandarin fish

mandarin fish

Sometimes the vivid coloured mandarin fish can be seen during the day hiding between hard corals. At dusk they come out for an hour or so to look for a mating partner. When they find one they will start swimming straight up from the corals close together where they mate which in that case means releasing the sperm and eggs into the water, also called a love cloud 😉


8) Wonderpus


The wonderpus is basically a type of octopus with very long arms and a distinct colour pattern. They use the long arms to hold on to rocks or corals while capturing the prey under their body or to get small prey out of holes. This type of octopus can only be found in some parts of Indonesia, the Philippines (Dumaguete for example, where I’ve seen them before) and a couple of other places.


9) Shrimp and Crabs


A countless number of different shrimp and crab species can be found at every single dive site.


10) Rhinopias


Rhinopias is a rare genus of scorpionfish that come in different forms and colours.  The one above is the only one I have seen so far. More to come 🙂


11) The maximum dive time is 75 minutes!

And your dive might even be longer if you find something fancy towards the end. In many places maximum dive times are anywhere between 45 and 60 minutes, depending on the air consumption as well. So in Lembeh you practically get almost 1 1/2 dives for the price of one.


12) Diving over black sand looking for small stuff (=muck diving) is fun

Even if it might not sound that appealing, it really is a lot of fun! I wasn’t bored for a single second diving in the Lembeh strait and there actually are a few dive sites which have some coral in the shallow areas. But do not expect beautiful reefs, there is only one pretty dive site and we did not have a chance to dive there because of strong currents.


13) You’ve never seen it all



zebra crab moray coleman shrimp dive lembeh shrimp boxer crab dive lembeh bluering octopus

I did see so many different new creatures during the 10 days I spent diving in the Lembeh strait but there is still more to explore. Like the bobbit worm, stargazer, hairy octopus and I am sure there are many more creatures to discover which I didn’t even know existed… I will be back!


Would  you like to go diving in black sand in order to find fancy creatures or do you prefer the big stuff?