All about the Paper Nautilus

Female Paper Nautilus have this distinctive shell on this back Argonauts can be found itching a ride on passing salp during blackwater dive

We first encountered this incredible little creature while Blackwater diving in 2017. At the time, we had absolutely no idea what we were looking at. ​ The first Argonaut we encountered was apparently a female, as male are 10 times smaller (rarely passing the size of 2cm) and dont have a shell. Since then, we’ve been lucky enough to spot Paper Nautiluses many more times — including during blackwater dives in the Similan Islands — and finally managed to capture a few decent photos. After some research, we discovered this strange and beautiful animal is called a Paper Nautilus, also known as an Argonaut. Despite the name, the Paper Nautilus is not actually related to the true nautilus. It belongs to the octopus family and is one of the ocean’s rarest pelagic cephalopods What is a paper Nautilus? The Paper Nautilus (Argonauta argo) is a species of open-ocean octopus found in tropical and subtropical waters around the world, including the Andaman Sea, Thailand, Myanmar, and the Similan Islands. The delicate white “shell” carried by females is not a true shell like a nautilus shell. Instead, it is a thin egg case secreted by the female using two specially adapted arms. ​ The female uses this paper-thin structure to: Protect her eggs Control buoyancy Shelter herself in open water Male Argonaut are tiny — often less than 2 cm long — and do not produce a shell at all.

​One of the Weirdest Mating Systems in the Ocean

Female Paper Nautilus riding a Jellyfish

Argonaut reproduction is famously bizarre. One of the male’s specialized arms acts as a reproductive organ called a hectocotylus. During mating, this arm detaches from the male’s body and remains inside the female to fertilize her eggs. The female then secretes the papery shell with the tips of two tentacles. She lays her eggs inside the paper shell and watch them until they are ready to hatch and her job is done. For many years, scientists thought these detached arms were actually parasitic worms because nobody had ever seen a complete male Argonaut. Nature is weird sometimes.

​The Paper Nautilus and Its Incredible “BCD”

One of the most fascinating things about the female Paper Nautilus is its ability to control buoyancy. Argonauts are the only known octopuses capable of trapping air from the ocean surface inside their shell-like egg case. The female swims to the surface, captures a small air bubble, seals the opening using her arms, then descends back into deeper water. This trapped air acts almost like a diver’s BCD (buoyancy control device), helping the Argonaut achieve neutral buoyancy and drift effortlessly through the open ocean. ​It’s one of the most unique buoyancy adaptations in the marine world.

Paper Nautilus Swimming

5 Amazing Facts About the Paper Nautilus​

This pelagic octopus uses jet propulsion to escape faster

🐙 1. The “shell” isn’t a shell at all! Female paper nautiluses don’t actually have shells; they build a delicate paper-thin case just to store their eggs. It’s basically the ocean’s most elegant Tupperware. 🐙 2. The male is so tiny he looks like he forgot to evolve. Females can grow up to 20 times larger than males. A male paper nautilus is hard to tell from other octopus you see on blackwater dives. 🐙3. They can “glide” underwater using jet propulsion .Like other octopuses, Paper Nautiluses swim using jet propulsion, expelling water through a siphon to move surprisingly fast through open water. Females may also use their delicate egg case to stabilize themselves while drifting in ocean currents. 🐙 4. Paper nautiluses ae true pelagic hitchiners They grab floating objects—seaweed, jellyfish, even trash—to ride ocean currents and save energy. They’re the backpackers of the sea, but with much better fashion sense. 🐙 5. They can transform into tiny air-sailors. ​By trapping air inside their paper-thin case, females can float at the surface like miniature balloons, rising and falling like they’re on a tiny ocean elevator.

Male argonauts can be hard to differentiate from other octopus

Male Paper Nautilus are much smaller and do not carry a shell

Where Can You See a Paper Nautilus? Paper Nautiluses are rarely seen during normal scuba dives because they live in the open ocean. The best chance of encountering one is during: Blackwater diving (Pelagic night dives) Night dives on remote offshore locations close to deep waters in tropical waters

They are pelagic hitchhikers, often found riding on salp chains like in this photo

​Why Divers Love the Paper Nautilus

Morays VS Eels VS Sea Snakes?

All morays are eels, but not all eels are morays and neither of them are snakes!
​​

Snake eels are usually burrowed in the sand

and their head is the only seen visible most of the time

Snake eel swimming on a blackwater dive

just like other snakes, banded sea krait need to breath air above water

​Snakes being reptiles (just like as turtles), they breathe through lungs and need to come up for air on a regular basis, even pelagic snakes who spend their lives offshore (learn more about sea snakes in this fascinating blogpost). pelagic sea snake is a freediving champion that can hold their breath up to 8 hours!

A few Moray & eels species encountered in the Andaman Sea

Giant moray eel:

White eyes moray eels :

Ribbon eels:

Ribbon Eel (Rhinomuraena quaesita)

Ribbon Eel (Rhinomuraena quaesita)

Ribbon Eel (Rhinomuraena quaesita)

Honeycomb moray:

Juvenile Honeycomb moray (Gymnothorax favagineus)

Another pretty species is the Honeycomb moray (Gymnothorax favagineus). Also known as the leopard moray, tessellate moray or laced moray, its body is white and covered with dark brown spots, evoking the coat of the leopard. adult Honeycomb moray another beautiful honeycomb in Burma Banks

Zebra moray:

Zebra Moray (Gymnomuraena zebra)

Zebra Moray (Gymnomuraena zebra)

Clouded moray:

Moreover, we can find the clouded moray (Echidna nebulosa), also called Snowflake moray. This moray is recognizable thanks to its light-colored body with two rows of large dark blotches along its sides. This species also has yellow eyes. They do not have sharp teeth but possess small blunt teeth. They feed mainly on crustaceans.

Fimbriated moray:

Bar-Tail moray:

Barred moray eel:

Mature adult Barred moray (Echidna-polyzona)

The Barred moray (Echidna-polyzona) is a species of moray eel found in the tropical waters of the eastern Pacific Ocean that holds manay names: Girdled Moray | Banded Moray | Barred Moray | Many Banded Moray Eel | Ringed Moray | Striped Moray | Zebra Eel. With a maximum length of about 1 meter, these eels have a distinctive appearance, featuring dark brown or black bands across their yellow or cream-colored bodies. They inhabit shallow coastal waters, including rocky reefs and coral reefs. Being nocturnal predators, they emerge from their hiding places at night to feed on small fish and crustaceans. While not much is known about their reproductive behavior, they are likely to be oviparous.

The Highfin Moray:

Highfin Moray (gymnothorax pseudothyrsoideus)

Yellow-headed moray:​

Yellow-headed moray (Gymnothorax rueppelliae) photo by Oren Kidron, Mergui Archipelago

Gymnothorax rueppelliae is most commonly known as the yellow-headed moray. This striking Indo-Pacific reef species is recognized by its contrasting dark brown body marked with pale vertical bands and its distinctly yellow to yellow-tan head. It inhabits coral reefs, lagoons, and outer reef slopes, hiding in crevices by day and emerging at night to hunt small fish and crustaceans. It is sometimes confused with the Gymnothorax fimbriatus, but the yellow-headed moray typically shows broader, more clearly defined pale bars that fully encircle the body and a comparatively cleaner, solid-colored head. The fimbriated moray, by contrast, usually has finer, more mottled banding and noticeable speckling on the head and jaws. Despite its sharp teeth and open-mouthed resting posture, the yellow-headed moray is generally shy and plays an important role as a nocturnal predator within reef ecosystems.

Tiger Reef eel:

Tiger Reef eel (Scuticaria tigrina)

The Tiger Reef eel (Scuticaria tigrina) is a rare species of moray eel primarily found in the coral reefs and rocky areas in the Indo-Pacific region. Other names for this funny critter: tiger reef-eel, tiger snake moray, tiger moray eel, tiger moray, tiger eel, spotted eel, or the spotted snake moray. Tiger Reef eel are primarily nocturnal predators, preying on small fish and crustaceans. They utilize their strong sense of smell and excellent camouflage to ambush their prey. Their elongated body, devoid of dorsal fin, is densely marked with dark blotches and can reach lengths of up to 70 centimeters.

Did you know?

You can even see eels on blackwater dives! Such a cool, alien-like critter!

You can even see eels on blackwater dives, such as this larvae

Exploring the Fascinating Sleep Patterns of Ocean Live

1/ Animal that can breathe underwater

Parrotfish Create a Protective Sleeping Bag Out of Their Own Mucus and Rest Inside it

Oceanic Manta Ray sleep in mysterious ways...

2/Animals that hold their breath underwater

Dolphins can put half of their brain to sleep and keep on swimming

Sperm Whales logging: they go in a state of rest, but are never entirely unconscious. Photo: IC/James Ferrara

Hawksbill Turtle taking a snooze under a rock

Conclusion

What makes Blackwater Diving So Special?

​1. Blanket Octopus (Tremoctopus spp.)  

​The Blanket Octopus (Tremoctopus spp.) is a striking deep-sea cephalopod known for the large, web-like membranes that trail from the arms of females, resembling a flowing blanket. This structure is used for defense, making the octopus appear larger to predators. Females can grow over 2 meters long, while males are tiny, rarely exceeding a few centimeters—one of the most extreme examples of sexual size dimorphism in the animal kingdom. Found in warm open oceans worldwide, Blanket Octopuses are solitary and rarely seen. They are capable swimmers and can detach parts of their web to distract threats. Remarkably, some use the stinging tentacles of Portuguese man o’ war as tools for defense and hunting.

2. Ctenophores (Comb Jellies)

​Comb jellies are among the longest-roaming invertebrate marine creatures on planet Earth. These carnivorous and voracious predators are delicate and gelatinous in structure. They possess eight rows of cilia-bearing plates used for “combing” and propelling themselves through the water. These plates can also produce and refract low levels of light. Their bodies are composed of more than 95% water and lack respiratory, circulatory, excretory, and skeletal systems. Some species, such as Beroe forskalii, have a mouth used for biting prey — often other ctenophores — and anal pores for excretion. Other species feature two tentacles covered with sticky cells called colloblasts, which are used to snare prey and draw it toward their mouths. Digestion occurs when enzymes liquefy the captured prey, with the remains expelled either through the mouth or the anal pores.

3. Eel Larvea

Eel larvae, known as leptocephali, are the transparent, ribbon-like early life stage of many marine eel species. Unlike typical fish larvae, leptocephali are laterally compressed, leaf-shaped, and nearly invisible in the water, offering excellent camouflage in the open ocean. They drift with currents for extended periods—sometimes months or years—feeding on dissolved organic matter and marine snow. During this pelagic phase, they grow before undergoing metamorphosis into the more cylindrical "glass eel" stage. From there, they begin their migration toward coastal habitats. The leptocephalus stage reflects the eel’s complex life cycle and plays a key role in marine ecosystems as both predator and prey.

4. Paper Nautilus (Argonauta argo)

The Paper Nautilus (Argonauta argo) is a rare pelagic octopus known for the delicate, paper-thin shell produced by females. Unlike true nautiluses, this shell is not for protection but serves as an egg case and buoyancy aid. Females can grow up to 30 cm and are significantly larger than the tiny, shell-less males. A. argo lives near the ocean surface and is found in warm and temperate seas worldwide. It preys on small crustaceans and jellyfish, using its webbed arms to capture food. The species is known for its graceful movement and is often seen floating or drifting with ocean currents. Despite its fragile appearance, the Paper Nautilus is a highly adapted and mysterious cephalopod, captivating scientists and divers alike with its unique reproductive behavior and ephemeral beauty.

5. Tripod Fish Larvae

Tripod Fish Youtube

Tripod fish larvae are the juvenile form of deep-sea tripod fish, typically belonging to the genus Bathypterois. Unlike their adult counterparts, which rest on the seafloor using elongated fin rays like stilts, the larvae are pelagic and drift in the open ocean. They are nearly transparent, with soft, delicate bodies adapted for life in the water column. As they develop, the characteristic elongated pelvic and caudal fin rays begin to form, eventually enabling the unique tripod stance seen in adults. These larvae feed on plankton and rely on ocean currents for transport. Their transition from free-floating juveniles to benthic ambush predators is one of the many fascinating adaptations of deep-sea life, reflecting the complexity of marine developmental stages in extreme environments.

6. Snake Blenny Larvae

Snake blennies  Blackwater diving - YouTube

Snake blenny larvae are the early life stage of elongated, eel-like fish in the family Stichaeidae, found in cold and temperate marine waters. Unlike the benthic adults that dwell near rocky or sandy substrates, the larvae are pelagic, drifting in the upper ocean layers. They are nearly transparent, with slender, ribbon-like bodies that offer camouflage from predators. Their large eyes and minimal pigmentation help them navigate and feed on microscopic plankton. As they grow, they begin to develop the characteristic elongated dorsal and anal fins of adult snake blennies. This transformation from a drifting larva to a bottom-dwelling fish illustrates the complex life cycle of many marine species, adapted for survival in both pelagic and benthic zones.

7. Amphipods

8. Pelagic Seahorses (Hippocampus spp.)

Pelagic Seahorse Blackwater diving - YouTube

Pelagic seahorses (Hippocampus spp.) are a rare group of seahorses that live in the open ocean, drifting with currents rather than anchoring to reefs or vegetation like most of their relatives. These seahorses are often found clinging to floating debris, seaweed, or Sargassum, using their prehensile tails for stability. Their bodies are upright, armored with bony plates, and capable of subtle color changes for camouflage. Pelagic seahorses feed on tiny planktonic crustaceans, sucking them in through their tubular snouts. Males carry fertilized eggs in a specialized brood pouch until giving birth to fully formed young. Their life in the open sea makes them difficult to study, but they are a vital part of surface marine ecosystems.

9. Larval Flounder

Flounder Blackwater diving - YouTube

The larval stage of flounders marks a dramatic transformation in these flatfish. After hatching, flounder larvae are symmetrical and free-swimming, resembling typical fish with an eye on each side of the head. As they develop, a unique metamorphosis occurs: one eye migrates to the opposite side, and the body flattens to adapt to a benthic lifestyle. During this stage, larvae drift in the plankton-rich upper ocean, feeding on microscopic organisms. Their bodies are mostly transparent, aiding in camouflage from predators. Once metamorphosis is complete, the juvenile flounder settles on the seafloor, lying on its blind side. This complex development allows flounders to exploit both pelagic and benthic environments during their life cycle.

10. Squid Larvea

Inshore Squid ​Blackwater diving - YouTube

Squid larvae, also known as paralarvae, are the early life stage of squids, emerging from eggs as miniature, free-swimming versions of adults. They are planktonic, drifting in the upper layers of the ocean where they feed on microscopic organisms. These larvae are transparent or semi-transparent, aiding in camouflage, and possess large eyes and developing tentacles. Unlike true larvae, squid paralarvae do not undergo a complete metamorphosis but gradually grow into their adult form. As they mature, they develop the muscular mantle, chromatophores, and jet propulsion used in adult locomotion. Squid larvae play a vital role in marine food webs, serving as prey for fish and other predators while beginning their own journey as agile hunters.

Blackwater Dive Briefing – Safety, Awareness & Expectations

​Blackwater diving is a thrilling and unique experience, but it requires preparation, awareness, and respect for others in the water to ensure a smooth and enjoyable dive for everyone. ​ What to Expect:  You’ll be tethered to a central downline, suspended in open water hundreds of meters deep, surrounded by darkness and illuminated only by strobes or torches. The environment can be disorienting at first, but it’s also incredibly exhilarating—offering glimpses of rare pelagic life. ​Safety & Prerequisites: ●  This dive is not for beginners—advanced certification and solid buoyancy control are essential. ●      Prior night diving experience is strongly recommended. ●      Always stay aware of your depth and proximity to the downline. For underwater photography, use a red focus light to avoid scaring away the animals. ​Diver Etiquette & Spatial Awareness: ●   Be mindful of your light control—waving your torch around can disturb marine life and irritate other divers. Avoid shining it in other people's eyes, especially when pupils are fully dilated in the dark. ●     Always be conscious of your 3D space: move slowly, maintain vertical awareness, and never swim directly under another diver—your bubbles can scare off the subjects they’re observing. ●      It's helpful to coordinate depth zones among divers during the briefing, allowing everyone enough room and reducing overlap. Agreeing on a depth rotation plan can also enhance everyone’s experience.

Personal Tip:

There’s no perfect depth—what works for one diver may not work for another. I find it useful to explore away from the group and return regularly to the main line. This gives space for quiet observation while maintaining a safe reference point. Stay calm, be respectful, and enjoy the mysterious magic of the blackwater world. ​

When and Where to Dive

In the Andaman Sea, between Thailand and Myanmar, we’ve been spotting more critters during the full moon — when tidal movement is at its peak. ​While blackwater diving is technically possible year-round, we only offer it during the national park season, which runs from October to May. ​All our cruises include one FREE blackwater dive when conditions are safe and suitable!

Book Your Blackwater Adventure!

The Spanish Dancer (Hexabranchus sanguineus) : A Must-See for Nudi lovers!​

Picture of a young Spanish dancer on the reef - Hexobranchus Sanguineus

Spanish Dancer : FAQ 1. What's so special about them? 2. Where can you see Spanish Dancers? 3. What do they Eat? 4. How do they reproduce? 5. Are they rare? 6. Are they dangerous? 7. Can they really swim?

What's so special about Spanish Dancers? ​Nudibranchs, (literally means naked gills) are divided into two main groups:  dorids and aeolids. Dorids breathe through feathery gill clusters on their backs, while aeolids have spike-like structures called cerata for respiration. ​Spanish Dancers are part of the dorid family, equipped with six fluffy tuft of gills which they can retract in individual pouches when they feel threatened. The Spanish Dancer standout among nudibranchs for several reasons. First, it is one of the rare nudibranch that can swim! When threatened, it unfurls its ruffled mantle in a graceful, undulating motion, much like a flamenco dancer’s skirt, which is how it earned its common name. Its brilliant red, orange, and pink coloration isn’t just for show—it’s a warning signal to predators that the creature is toxic. In addition to its dazzling appearance, it’s one of the largest nudibranchs, sometimes reaching impressive sizes (up to 90cm!) that make it a favorite subject for underwater photographers and marine enthusiasts alike.​

Anatomy of nudibranch - Dorid VS Aeolid

Where can you see Spanish Dancers? Spanish Dancers are typically found in warm reef environments at depths of 5 to 30 meters and are most common in tropical waters across the Indo-Pacific. ​Notable locations include the Philippines, Indonesia, Papua New Guinea, Australia, and Hawaii, as well as renowned dive sites like the Great Barrier Reef, Raja Ampat, Anilao, Maldives, and the Red Sea. These creatures thrive in pristine, healthy reefs where temperature, salinity, and water quality are maintained—but they are highly sensitive to pollution and habitat degradation, which can severely impact their survival. Seeing them is one of the indicators of a healthy reef! In the Andaman Sea these superbe nudibranchs are known to reside in shallow reefs—often hiding in crevices during the day and emerging at night. More common in Mergui Archipelago, Myanmar but also often sighted in Thai Waters, diving here offers excellent opportunities to witness the Spanish Dancer in its natural habitat.

Spanish Dancer Unfurling Its Mantle or Parapodia

Spanish dancers are carnivorous sponge eaters

What do Spanish Dancers eat? Spanish Dancers are carnivorous and primarily feed on various sponges—a diet that is essential for their survival. ​They are known to feed on species from the Halichondriidae family, among others, and in doing so, they accumulate chemical compounds that they later use as a defense mechanism.  Their feeding habits not only sustain them but also help regulate sponge populations within the reef ecosystem.

Spanish Dancer lay they Eggs in a spiral pattern

Spanish dancer's eggs are also called Ocean rose

Are Spanish Dancers Rare? ​While the Spanish Dancer is not commonly encountered on every dive, it isn’t classified as extremely rare either. They are typically found in healthy coral reef ecosystems where sponges abound. Their elusive nature—often hiding during daylight and emerging at night—means that spotting one during the day is very rare! The best time to observe a Spanish Dancer is during a night dive. These nocturnal creatures become most active after sunset, emerging to feed, mate, and explore the reef. Watching them twirl through the water under the glow of a dive torch is an unforgettable experience for any underwater adventurer. ​ In Myanmar, we've got a dive site we nicknamed Spanish Garden because of the number of Spanish dancer we've met there!

Are Spanish Dancers Dangerous? Spanish Dancers are not dangerous to humans and they do not possess a sting, nor are they venomous in the traditional sense. Instead, they accumulate toxins from the sponges they consume. These toxins serve as a chemical defense making them less attractive to potential predators. While these compounds can deter natural enemies, divers can safely admire the Spanish Dancer without fear of being harmed. Bonus: These toxins are even passed to their eggs ribbons giving a better chance to young ones to hatch!

Yes, the Spanish Dancer is one of the few nudibranchs with the ability to swim! Although they typically crawl along the seabed, when disturbed they extend their wide, flared mantle (called parapodium) and propel themselves through the water using rhythmic, undulating contractions. ​This dynamic swimming behavior, reminiscent of a flamenco dancer’s swirling skirt, is one of the features that makes them so captivating to watch underwater. This graceful movement is both a survival tactic and a spectacle to witness. When disturbed, the Spanish Dancer can use this motion to quickly escape predators, making it one of the most agile nudibranchs in the ocean.

Did you know? ​Emperor Shrimps: Hitchhiking in Style

Emperor shrimp is the Spanish dancer's symbiotic partner Spanish Dancer with 2 emperor partner shrimps

Anatomy of the Spanish Dancer Spanish dancers have a unique anatomy that helps them navigate and survive in their marine environment. Their 6 gills, arranged in a circle around their anus, are located on the tail end of the upper side of their flattened bodies, allowing them to efficiently breathe underwater. The rhynophore, a pair of antenna-like structures on their head, helps them detect chemicals and movement in the water, providing them with a sense of their surroundings. Their mouth is equipped with oral tentacles, which they use to grasp and manipulate sponges they feed on. A muscular foot on their underside allows them to crawl along the seafloor, while their mantle, a large, flared structure on their back, typically coils alongside their body. When threatened, the parapodia, the extremity of the mantle, can unfurl, allowing them to "fly" away in the most elegant - flamenco dancing - manner.

Conclusion: A nudi to add on your night diving bucket list!

Whether you’re cruising through the vibrant reefs off the coasts of Burma and Thailand or exploring the diverse underwater habitats of the Indo-Pacific, the Spanish Dancer offers a breathtaking glimpse into the wonders of marine life. With its dazzling colors, graceful swimming, and intriguing reproductive habits, this nudibranch truly embodies the artistry of Mother Nature. ​So next time you go on a night dive, keep your eyes peeled for this marine marvel—you’re in for a show that’s as elegant as a flamenco performance!

🎭 Master of Disguise: What Is an Ornate Ghost Pipefish?

🔍 Where to Spot One: Habitat & Behavior

​You’ll most likely find Ornate Ghost Pipefish in sheltered, sandy areas of coral reefs, especially: ​ Among crinoids, which they mimic with startling accuracy Hanging near soft coral fans or gorgonians Close to the reef bottom, where they can hover in the current unnoticed ​They prefer calm conditions and tend to show up in specific sites year after year, often returning to similar spots when conditions are right. 🌊 Top Dive Sites to See Them: Shark Cave (Mergui Archipelago, Myanmar), Richelieu Rock, Hin Daeng, Hin Muang (Andaman Sea Thailand)

📆 Best Time to See Them: November to April

🔬 The Life Cycle & Reproduction of a Ghost

💑 Courtship & Mating During the breeding season, usually aligned with peak visibility months, males and females pair up and are often seen drifting side-by-side in gentle currents. Their courtship is subtle, consisting of synchronized movements and gentle displays. 🥚 Unique Egg-Carrying Behavior The female takes on the primary reproductive role—not only producing the eggs but also carrying them. Her pelvic fins fuse to form a specialized brood pouch—a kind of open "sac" where she stores fertilized eggs.   She can carry up to several dozen eggs at a time, offering them protection and oxygenation through gentle fin movement. This behavior is rare in fish and more commonly associated with their relatives, the seahorses (where males carry eggs). In ghost pipefish, however, it’s the female who guards and nurtures the young.

🐣 Hatching & Lifespan

📸 Pro Tips for Divers & Underwater Photographers

🌊 Why Seeing One Is So Special

🎒 Dive Into the Mystery with The Smiling Seahorse

The Smiling Seahorse

​By Clément 

What are Guitarfish? "A Ray That Looks Like a Shark"

Bowmouth guitar fish - Burma banks 2024

"Rare Encounter: Bowmouth Guitarfish at the Burma Banks

The lower jaw of the bowmouth guitarfish (Rhina ancylostoma) features teeth with rounded, ridged surfaces, perfectly adapted for crushing the shells of their prey. Photograph: King’s College London.

Diet: What do guitar shark eat? Guitarfish are bottom feeders, primarily consuming crustaceans, mollusks, and small fish that inhabit sandy or muddy seabeds. Their flat teeth are designed to crush the hard shells of their prey, allowing them to feed on a variety of sea creatures that many other predators cannot. One fascinating adaptation of bowmouth guitarfish is their rows of shark-like spines along their backs. These spines serve as a natural defense mechanism, deterring predators such as larger sharks. Unfortunately they are also sold in Asia as luxury jewellery ornament.

Reproduction of the guitar rays

Are guitar sharks dangerous?  Despite their imposing size—some species, like the giant guitarfish on the right, can grow up to 3 meters (9.8 feet)—guitarfish are entirely harmless to humans.  ​ They are gentle creatures whose primary predators include larger sharks, such as Tiger sharks, and humans due to overfishing. ​Unfortunately, many species of guitarfish are now classified as vulnerable or endangered.

Giant guitarfish, also known as the whitespotted wedgefish (Rhynchobatus Australiae) - photo by Yon Soponwit

​​Conservation Status: A Species Under Threat

Bowmouth guitarfish thorns are use in Thai traditional jewellery - Photo by: Shin Sirachai Arunrugstichai

They are also fished for their valuable fins and by mistake in large nets. Photo by : Shin Sirachai Arunrugstichai

Fun Facts About Guitarfish

Bowmouth guitar fish coming curiously to check us out at the Burma banks

Where can you see Guitarfish

Shovel nose guitar fish - Black Rock

These shovelnose rays (Rhinobatos ranongensis) were spotted by hundreds on the deeper parts of Black Rock, north of Mergui Archipelago, it was a carpet of them in the depths around the dive site. They like colder water and often show up when water temperature drop.  These rays camouflage themselves so well by burrowing into the sandy seabed, it took us a while to spot one and then we saw so many!!!

4 incredible fun facts about the peacock mantis shrimps!

** Mantis Shrimp ​Fun Fact #2: Super Smashers of the Ocean** Peacock mantis shrimp are not just pretty. They are ferocious predators with a pair of specialised front limbs that can strike with the speed of a bullet! Their clubs can deliver blows with the force of a .22 caliber bullet, and they use this power to break open the shells of prey like crabs and snails they love. The mantis shrimp's hunting prowess is so legendary that it's even been known to break aquarium glass. It's not a pet you'd want to mess with! Curious mantis shrimp in Koh Lanta National Park

Peakock mantis shrimp and amazing coral reef ** Mantis Shrimp Fun Fact #3: Color Vision Extraordinaire** Mantis shrimp vision is the stuff of science fiction. While we humans have three color receptors, these oceanic superheroes have sixteen! They can see polarized light, ultraviolet, and colors that are beyond our comprehension. This super-vision helps them spot prey, predators, and mates with astonishing clarity.

An interesting life cycle

Smasher vs Spearer Mantis Shrimp

​Now, let's answer some of the most common questions people ask about peacock mantis shrimp:

**1. Can peacock mantis shrimp see more colors than humans?** Humans have three color receptors (red, green, and blue cones), allowing us to perceive a wide range of colours. Peacock mantis shrimp have an astonishing sixteen (or more) colour receptors, enabling them to see colours beyond human comprehension, including ultraviolet light and polarized light. In the underwater realm, the peacock mantis shrimp's eyes are a true anomaly. Their ability to see a rainbow of colors and polarized light sets them apart as one of the ocean's most visually gifted inhabitants. In comparaison, horses or dogs, are called dichromatic, meaning they have two primary color receptors or cones in their eyes. Less than humans and much much less than Mantis Shrimps!

Supersonic Vision!

Bullet fast punch!

**2. How fast is the peacock mantis shrimp's punch?** The peacock mantis shrimp has one of the most powerful and fastest punches in the animal kingdom. It possesses specialized appendages called "raptorial appendages" that it uses to strike its prey. These appendages, also known as "smashers," are highly dexterous and possess incredible strength. When a peacock mantis shrimp strikes, it accelerates its "hammer like appendage" at an astonishing speed of 23 meters per second. This unbelievable speed generates an impressive amount of force, with some estimates suggesting that it can exert up to 1,500 Newtons, which is equivalent to a bullet being fired from a .22 caliber rifle!

**4. How do peacock mantis shrimp communicate with each other?** These mantis shrimp often use a combination of visual signals and body language for communication. They display various color patterns and postures to convey information about their intentions, such as territorial disputes or courtship rituals. **5. What are some interesting behaviors of peacock mantis shrimp?** Peacock mantis shrimp are known for their meticulous burrowing behavior. They construct intricate burrows with multiple chambers, which serve as both protection and a place to ambush unsuspecting prey. They are also quite territorial and will fiercely defend their burrows. **6. Can peacock mantis shrimp regenerate their limbs?** Yes, peacock mantis shrimp have a remarkable ability to regenerate their limbs if they get injured or lose one during battles or accidents. Their powerful resilience is another testament to their extraordinary adaptations.

**7. Where can you find peacock mantis shrimp in the wild?** Peacock mantis shrimp inhabit the warm waters of the Indian and Pacific Oceans, particularly in the tropical coral reefs. You can often spot them in rocky crevices and burrows along the seafloor. While amazing and incredible creatures, Mantis shrimps are not rare in our dives and and our guides see them on every single one of our Andaman Sea adventures. Wanna know more about the Marine Life of the Andaman Sea? Check out this page for reference!

Reef clown or reef hunter?

Sex on the reef when you're a frogfish

Frogfishes are also known for their unique mating habits. When female frogfish are ready to mate, they start producing eggs, causing their bellies to swell and become more buoyant. This attracts male frogfish, who will then nudge the female until they are both floating on the surface. At this point, the female will release her eggs, forming a gelatinous raft that the male will fertilize. Some species leave these rafts to float in the open ocean, while others attach them to their bodies or the ocean floor and guard them until they hatch. ​ Females can produce between 40,000 and 180,000 eggs per season, and the resulting fry emerge from the eggs after 2-5 days looking like tiny jellyfish with long fin filaments. After a few months, they begin to take on the same coloration as poisonous sea slugs, which helps them avoid being eaten by larger fish and other predators. Eventually, the fry will settle onto a reef and stay there until it is time to mate again.

3 fun facts about frogfishes that you should know about!

Frogfish Identification

One common species of frogfish found in the Indo-Pacific region is the giant frogfish (Antennarius commerson). This species can reach up to 30 cm in size and is distinguished by its long rod (called an illicium) and small, bushy esca (lure) with fine, long filaments. The giant frogfish also has thick, bulb-like second and third dorsal spines.

Another species found in the region is the freckled frogfish (Antennarius coccineus), which grows up to 10 cm in size and has an illicium of the same length as its second spine. This species has a small tufted esca with dark swellings at the base and lacks a distinct tail base, which distinguishes it from the similar-looking spotfin frogfish.

The warty frogfish (Antennarius maculatus) is another commonly encountered species, growing up to 8-10 cm in size and having an illicium that is twice as long as its second spine. This species is easily recognizable by its warty skin, triangular patches radiating from its eye, and a thin membrane on its second and third dorsal spines. Its esca is designed to mimic small fish or shrimp and has an "eye spot."

The painted frogfish (Antennarius pictus) is a rarer species in the Indo-Pacific, growing up to 15 cm in size and having an illicium that is twice as long as its second spine. It is distinguished by its bushy esca with compressed appendages and can be easily confused with a juvenile giant frogfish. However, the painted frogfish has three spots on its tailfin and can also have a color phase similar to the warty frogfish, but with triangular markings that do not radiate from the eye.

The striated or hairy frogfish (Antennarius striatus) is another species found in the region, reaching up to 20 cm in size and having an illicium of the same length as its second spine. It is distinguished by its distinctive stripe pattern and its esca, which has large, worm-like appendages.

credit- Christian Gloor

The sargassum frogfish (Histrio histrio) is a species that is leaves offshore, typically found in sargassum weed drifting in the ocean, and therefore is rarely seen by divers. It grows up to 15 cm in size and has an illicium that is half the length of its second spine, as well as a small esca with folds. We got extremely lucky to spot this fellow near the surface to get this beautiful triple reflection! ​(only one frogfish here, the bottom one...)

The psychedelic frogfish (Histiophryne psychedelica) is a very distinctive species with a freaky appearance. It has only been found in a few places around Ambon and is thought to live very deep, coming to diveable depths only to breed. It grows up to 5 cm in size and lacks an illicium and esca.

Credit Wikimedia Commons, the free media repository

​Here are some tips on how to spot, photograph, and appreciate the unique characteristics of these masterful creatures.

Spotting Frogfishes 

Improve your frogfish shots!