Marine Life in Thailand
Meet the sharks, rays, turtles, reef fish, macro creatures, corals and curious underwater animals divers may encounter across Thailand.
What you may see while diving in Thailand
Marine-life sightings vary by region, season, water conditions and luck. The Andaman Sea is especially noted for offshore pelagics and colourful soft-coral sites, while the Gulf of Thailand offers productive reefs, wrecks and famous pinnacles.
GiantsWhale Shark
Rhincodon typusThe world’s largest fish and one of Thailand’s most memorable encounters. Usually seen cruising open water around offshore pinnacles, especially in the Andaman Sea and around Sail Rock.
GiantsGiant Manta Ray
Mobula birostrisA graceful filter-feeding ray often seen at cleaning stations and exposed offshore sites. Keep your distance and let the animal choose the encounter.
GiantsReef Manta Ray
Mobula alfrediSlightly smaller than the giant manta and commonly associated with reefs and cleaning stations. Best chances are at current-swept pinnacles.
Sharks & RaysBlacktip Reef Shark
Carcharhinus melanopterusA sleek, shy reef shark frequently seen in shallow lagoons and around island reefs. It normally keeps its distance from divers.
Sharks & RaysWhitetip Reef Shark
Triaenodon obesusA nocturnal reef shark that often rests beneath ledges during the day. Look for the distinctive white tips on its fins.
Sharks & RaysLeopard / Zebra Shark
Stegostoma tigrinumA gentle bottom-dwelling shark with a long tail. Adults have a spotted pattern and are often seen resting on sandy areas beside reefs.
Sharks & RaysGrey Reef Shark
Carcharhinus amblyrhynchosA powerful open-water reef shark found around drop-offs, pinnacles and stronger currents. Most sightings occur at remote Andaman sites.
Sharks & RaysEagle Ray
Aetobatus ocellatusRecognisable by its spotted back and pointed wings. Eagle rays often glide over sandy channels or pass reef edges in blue water.
Sharks & RaysBlue-spotted Stingray
Taeniura lymmaA small, brightly marked ray usually found resting beneath coral shelves or moving over sand. Its electric-blue spots are unmistakable.
Turtles & ReptilesGreen Sea Turtle
Chelonia mydasA large herbivorous turtle commonly seen feeding on seagrass or resting beside coral reefs. Never touch, chase or block its route to the surface.
Turtles & ReptilesHawksbill Turtle
Eretmochelys imbricataA reef-feeding turtle with a pointed beak and patterned shell. It is often seen searching coral for sponges and small invertebrates.
Turtles & ReptilesBanded Sea Krait
Laticauda colubrinaA black-and-white sea snake that hunts eels and small fish. It is venomous but generally calm and uninterested in divers.
Pelagic FishGreat Barracuda
Sphyraena barracudaA long silver predator that may hover alone near reefs or patrol in open water. Schools of smaller barracuda can form spectacular spirals.
Pelagic FishGiant Trevally
Caranx ignobilisA muscular, fast-moving hunter often seen around pinnacles and current lines. Large individuals are impressive but usually pass quickly.
Pelagic FishTuna
ThunniniFast pelagic predators that appear around offshore sites when baitfish are present. Dogtooth tuna are particularly prized sightings.
Pelagic FishBatfish
Platax spp.Tall, silver fish that often gather around wrecks, mooring lines and pinnacles. Juveniles look dramatically different from adults.
Reef FishClownfish
Amphiprion spp.Small territorial fish living among sea anemone tentacles. Thailand has several species, often seen in pairs or family groups.
Reef FishButterflyfish
ChaetodontidaeBrightly patterned reef fish usually seen in pairs. Their presence and feeding behaviour make them excellent subjects for photographers.
Reef FishAngelfish
PomacanthidaeColourful, laterally compressed fish that patrol reef walls and coral gardens. Juveniles often have completely different patterns.
Reef FishParrotfish
ScaridaeImportant reef grazers with beak-like teeth. They scrape algae from coral surfaces and help create fine tropical sand.
Reef FishTriggerfish
BalistidaeStrong-jawed reef fish with distinctive swimming motion. Titan triggerfish can be territorial during nesting season, so give them space.
Reef FishMoray Eel
MuraenidaeSecretive reef predators that shelter in crevices with only the head visible. Their open-mouth posture is breathing, not aggression.
Reef FishLionfish
Pterois spp.A slow-moving ambush predator with ornate venomous spines. Beautiful to photograph, but never touch.
Reef FishScorpionfish
ScorpaenidaeMasters of camouflage that blend into rock and coral. Their dorsal spines are venomous, making careful buoyancy essential.
Reef FishPufferfish
TetraodontidaeRounded fish with powerful beaks and expressive faces. Inflation is a stress response, so never provoke one for a photograph.
Reef FishNapoleon Wrasse
Cheilinus undulatusA huge, long-lived wrasse with thick lips and a prominent forehead. Encounters are uncommon and always memorable.
CephalopodsReef Octopus
Octopus cyaneaAn intelligent camouflage specialist capable of changing colour and texture almost instantly. Look for moving shells and disturbed sand.
CephalopodsCuttlefish
SepiidaA highly visual cephalopod that communicates through rapidly changing skin patterns. Courtship and hunting displays are spectacular.
CephalopodsSquid
TeuthidaFast-swimming open-water cephalopods often attracted to lights on night dives. Small schools may hover just beyond torch beams.
Macro LifeNudibranch
NudibranchiaColourful shell-less sea slugs prized by macro photographers. Thailand’s reefs support a huge variety of shapes, colours and sizes.
Macro LifeSeahorse
Hippocampus spp.Small, well-camouflaged fish that grip coral, sponge or debris with a prehensile tail. Best found with a patient local guide.
Macro LifeGhost Pipefish
SolenostomidaeDelicate fish that imitate leaves, crinoids or drifting debris. They are seasonal and exceptionally well camouflaged.
Macro LifeFrogfish
AntennariidaeA stocky ambush predator that walks on modified fins and uses a lure to attract prey. Colour and texture vary enormously.
Macro LifeCleaner Shrimp
Lysmata spp.Tiny shrimps that operate cleaning stations, removing parasites from fish. Watch for their waving antennae inside reef crevices.
Macro LifeHarlequin Shrimp
Hymenocera pictaA spectacularly patterned shrimp that feeds on sea stars. It is uncommon and a prized find for underwater photographers.
InvertebratesCrown-of-thorns Starfish
Acanthaster spp.A large coral-eating starfish covered in venomous spines. Natural in low numbers, but outbreaks can seriously damage reefs.
InvertebratesBlue Sea Star
Linckia laevigataA vivid blue starfish commonly seen crossing coral and rubble. It is one of the most recognisable Indo-Pacific reef animals.
InvertebratesLong-spined Sea Urchin
Diadema setosumA dark sea urchin with extremely long, fragile spines. It grazes algae but should be given plenty of clearance.
InvertebratesGiant Clam
Tridacna spp.Large reef molluscs with brightly coloured mantles containing symbiotic algae. They remain fixed in place and filter seawater.
InvertebratesFeather Star
CrinoideaA delicate relative of starfish with many feathery arms. It clings to coral and catches drifting plankton, especially in current.
InvertebratesSea Cucumber
HolothuroideaSlow-moving sediment feeders that recycle nutrients and help keep reef sand healthy. Many species are active at night.
Corals & Reef LifeHard Corals
ScleractiniaReef-building corals that create the physical structure of Thailand’s coral ecosystems. Common forms include branching, massive, plate and brain corals.
Corals & Reef LifeSoft Corals
AlcyonaceaFlexible, often brightly coloured corals that flourish on current-swept walls and pinnacles. They do not build a hard limestone skeleton.
Corals & Reef LifeSea Fans
GorgoniansLarge fan-shaped colonies positioned across currents to catch plankton. They are especially impressive on deeper Andaman walls.
Corals & Reef LifeSea Anemones
ActiniariaSoft-bodied relatives of corals with stinging tentacles. Many host clownfish, porcelain crabs and specialised shrimps.
Corals & Reef LifeBarrel Sponge
Xestospongia spp.Large filter-feeding sponges shaped like barrels or chimneys. They provide shelter for tiny reef animals and process enormous volumes of water.
Observe safely
Keep your distance. Let wildlife control the encounter.
Protect the reef. Maintain neutral buoyancy and secure loose equipment.
Never touch. Many corals and animals can sting, bite or be damaged by contact.
Follow your guide. Local dive professionals understand site conditions and animal behaviour.
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