Last Updated on July 9, 2025 by Dan
Mysteries in the Volcanic Sand: A Beginner’s Guide to Muck Diving in Bali
Muck dives are my most favorite dives and it breaks my heart that so many people still have no idea what they are. Let me explain, and hopefully inspire another macro enthusiast to explore the ocean floors, searching for the most bizarre and photogenic marine creatures Mother Earth has to offer.
Muck diving is the art of exploring sandy, silty, or “black sand” bottoms rather than colorful coral reefs. While it might sound unremarkable, in muck diving sites, sand is full of surprises and critters that you never knew existed. From tiny seahorses camouflaged in algae to flamboyant nudibranchs inching over the seabed, muck diving brings you face-to-face with rare macro species you just won’t see on the reef. It’s a real eye-opener to those who think that sand is boring. Let’s dig into some special eye-candies you might encounter with an experienced guide in Bali leading your dive.
Seraya Secret – Home of the Pygmy Seahorses & Harlequin Shrimp
This dive site, located in Tulamben and accessible right there from the shore, is a mix between dramatic black sand and separate coral strips, sloping down all the way to 30 meters, where a massive, vibrant gorgonian sea fan awaits. This sea fan is home to the cutest of them all – pygmy seahorse. About the size of a jelly bean (1 – 2 cm), their bodies sport knobbly tubercles that match the polyps of their host coral, in hues from bright pink or purple to yellow and orange. Even when the dive guide points right at this marvel, newer divers might need some time to spot it, as it’s so well camouflaged. One of the nicest sounds to hear as a dive guide under water, is when your guest finally sees what you are showing – its a mix of surprise, admiration, disbelief all in one “awwww”.
Another amazing creature often found in this site is the Harlequin shrimp. Measuring up to 3 cm they have a creamy white base adorned with bold purple-blue or reddish spots edged in purple—each individual’s pattern is slightly different, like an underwater fingerprint. Typically found in monogamous male-female pairs that hunt together and defend a feeding territory, they feed almost exclusively on starfish.
Last but not least, on the way back to the shore, your dive guide might show you an ornate ghost pipefish. These will seem as giants compared to previous gems, as they range from 5-15 cm in length, however, still fantastically hidden in their hosts, usually feather starfish.
Sidem – Next Level Macro Site With Frogfish and Seahorses
Located in Batu Belah, near Tulamben, Sidem is a pure sand, algae and pebble mix with never ending critters to offer. There are far fewer corals than in Seraya Secret, focusing your attention directly on the seabed without distractions. As a pure macro site, it’s rarely crowded.
It’s amazing how well the local guides can navigate what looks like endless sand and pebble bottom, to bring you right to the well hidden gems. The main character here is the frogfish, masters of camouflage that can change color and texture to blend into their surroundings and use a lure to attract prey. Despite their chunky look, they can expand their mouths to 12 times their size to engulf prey nearly as big as themselves. Frogfish range from tiny 1 cm juveniles to large adults up to 15 cm but remain hard to spot.
Other critters include boxer crabs, commonly called pom-pom crabs because they hold tiny anemones in their claws for defense and hunting—tiny, well-hidden, and a real celebration to find. Beginner divers will love the classy spiny seahorses, which hold onto whatever they can to anchor themselves for a never-ending dinner, as they have no stomachs and can eat up to 3,000 tiny items per day.
Throughout your search for these critters, you’ll see plenty of never-before-seen nudibranchs. Often called sea slugs or sea bunnies, more than 3,000 species have been described worldwide, with over 300 species found in Bali alone. Some are smaller than the eye can see, others grow up to 15 cm—all in different shapes and colors. Some are solar-powered; others are kleptocnidae thieves, stealing stinging cells from their prey and reusing them for defense. All are stunningly beautiful, some of the ocean’s coolest hidden gems—often missed by divers unless guided by a fellow macro lover into the weird and wonderful world of muck diving.
Must Have Skills for Muck Diving – Buoyancy is Everything
Muck diving can only be enjoyed when your buoyancy skills are top-notch. As an active dive instructor, I cannot stress enough how important good buoyancy is – it is without a doubt the most important skill when diving. Yet many divers skip this step during their training. Poor buoyancy doesn’t just ruin your own dive—it can damage the site and negatively affect everyone else’s dive as well.
As the dive industry becomes increasingly fast-paced, some places now offer Open Water certifications in as little as two days. With so much to cover in such a short time, the schedule is extremely tight and often leaves little room for truly mastering essential skills.
Buoyancy is a skill that takes time to master. Even changing part of your gear or diving in a different ocean can affect your buoyancy. PADI’s Peak Performance Buoyancy specialty is a worthwhile investment—not just for muck diving, but for all your future dives. Many divers believe they need 8 kg of weight simply because they haven’t been taught how to use body position, breathing, and gear to their full potential. Being overweighted is one of the worst things a new diver can do—to themselves, their bottom time, and the environment.
During a regular fun dive, there’s often no time or focus to properly test and fine-tune your buoyancy, as there are too many distractions. But if you take the Peak Performance Buoyancy course with an instructor who truly cares, you’ll be forever grateful you invested the time and those two dives to master the most important skill in diving.
The PADI Peak Performance Buoyancy (PPB) Specialty consists of a short knowledge development section—either in person or online—where you review buoyancy principles, weighting, trim, and breathing techniques. You’ll then complete two open water dives with an instructor. During these dives, you’ll practice fine-tuning your weighting, adjusting body position, hovering, and navigating buoyancy challenges through fun, skill-focused exercises. With a superb instructor, you might even practice backwards finning, helicopter spins, and other exercises to fully control your body position in any situation. In my six years as an instructor, I have never met a person disappointed with this training.
Must Have Gear for Muck Diving
Dive pointer sticks let you point to tiny marine creatures without crowding them. They can also be used as a “tank banger” to get attention and are helpful for balancing yourself underwater. Available in different shapes and colors, they can match your dive gear, and many include an integrated ruler so you can show exactly how small the wonders you’ve found really are.
In some marine parks they are forbidden, as many divers use them to abuse marine life. Please do not be one of them. Respect the ocean.
GoPro Macro Lens Mod is the only way how you can take photos and videos of small critters using your GoPro camera. Without this lens, your GoPro is completely useless during muck dives. The lens allows you to get up to 4× closer, reduces minimum focus distance to just a few inches and produces crisp, high-contrast close-ups. It’s unbelievable how good it works and even without an expensive underwater camera you can create great visuals! It is super easy to use, as it hangs on magnetically for quick swap-outs between wide and macro shots. Just make sure you keep your GoPro housing clean from sand to protect the lens.
I would like to stress again that even GoPro with a Macro Lens Mod won’t work if your buoyancy is not mastered yet.
Nitecore DL30 (1,100 lumens) – no muck-dive setup is complete without a reliable light. This one is an excellent choice: compact and waterproof to 100 m, its tight beam allows you to highlight tiny critters with sharp contrast. The single-button interface and lock-out feature make it easy to operate. Whether you mount it on a hand strap or use a clip, this light will be a great addition to your muck diving gear. Many divers prefer video or focus lights, but a reliable spot torch is more versatile and easier to manage, especially for beginners.
Muck diving in Bali is a fantastic opportunity to expand your awareness of marine life and upgrade both your diving skills and comfort level. It’s not all about sharks and turtles—there’s so much more to discover when you’re ready to look closer. Once you’ve truly mastered your buoyancy, diving becomes not only more enjoyable but also safer for both you and the environment. After learning to control your body, breathing, and basic gear, you can comfortably add a camera, lights, and a pointer stick to your setup and get the most out of every dive.
I hope you’re ready to become a better diver—and to see more than meets the eye beneath Bali’s black sands.
