Fish of Koh Tao: Your Guide to What You’ll See While Diving with Chalok Reef Divers
Introduction
This is the fifth installment in our blog series exploring the vibrant and diverse marine life around Koh Tao. In this part, we’ll uncover more remarkable marine creatures, from peculiar pufferfish to colorful wrasses. Every dive is a chance to meet these underwater characters up close! In case missed it click for Part 4 of our Koh Tao Fish guide.
Blacktip Tuskfish
About: The Blacktip Tuskfish is a bold and inquisitive reef dweller, easily recognized by its sharp teeth and distinctive black tips on its fins. These fish are often seen roaming sandy bottoms or darting between coral heads.
How Common? Fairly common, especially in areas with mixed sand and coral.
Fun Fact: Blacktip Tuskfish are known to use tools! They’ve been observed smashing shells on rocks to access their prey.
Commonly Found At Dive Sites:
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Hin Ngam
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Tanote Bay
Blotched Porcupinefish
About: The Blotched Porcupinefish is a round, spiky marvel that inflates itself when threatened. With its spotted body and large, expressive eyes, it’s a favorite among divers.
How Common? Occasionally seen, often hiding in crevices or under overhangs.
Fun Fact: Despite their cute appearance, their spines and potent toxins make them a formidable foe for predators.
Commonly Found At Dive Sites:
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Chumphon Pinnacle (often hiding near the coral bowl base)
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Laem Thian Caves
Mapped Pufferfish
About: The Mapped Pufferfish is a stunning species with intricate, map-like patterns on its body. These fish are slow movers, often found near the seabed or grazing on sponges.
How Common? Fairly common, particularly in sheltered reef areas.
Fun Fact: Like all pufferfish, they can inflate their bodies to deter predators, making them look like underwater balloons.
Commonly Found At Dive Sites:
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Hin Ngam
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Twins (sheltered western side)
Harlequin Sweetlips
About: The Harlequin Sweetlips is an eye-catching fish with its spotted body and playful swimming style. Juveniles are particularly fascinating, with exaggerated movements that mimic floating leaves to confuse predators.
How Common? Occasionally seen but always a delight to encounter.
Fun Fact: Sweetlips get their name from their large, pouty lips, which they use to sift through the sand for food.
Commonly Found At Dive Sites:
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Aow Leuk (juveniles along rocky coral base)
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Green Rock (juveniles near swim-throughs)
Whitebelly Damselfish
About: The Whitebelly Damselfish is a feisty little reef dweller with a striking white belly and bold black markings. These territorial fish can often be seen chasing away intruders near their chosen coral home.
How Common? Very common and easy to spot.
Fun Fact: Damselfish have a symbiotic relationship with algae, which they cultivate and protect on the reef.
Commonly Found At Dive Sites:
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Tanote Bay
Doublebar Rabbitfish
About: The Doublebar Rabbitfish is a striking herbivore with bold black bars running along its body. These fish are often seen in pairs, grazing on algae and helping maintain the health of the reef.
How Common? Fairly common, particularly in areas with abundant algae growth.
Fun Fact: Rabbitfish spines are venomous, so predators think twice before attempting to snack on them.
Commonly Found At Dive Sites:
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Hin Ngam
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Mango Bay (southern reef area)
Longspine Squirrelfish
About:
The Longspine Squirrelfish (Sargocentron spiniferum) is a striking nocturnal reef dweller, easily recognized by its vivid red body, oversized eyes, and spiny dorsal fin. These solitary fish spend their days tucked away in rocky crevices and caves, becoming more active at night when they emerge to feed on small crustaceans and invertebrates.
How Common?
Fairly common around Koh Tao, especially spotted on night dives when they’re most active.
Fun Fact:
Longspine Squirrelfish are among the few reef fish that “talk”—they make clicking or grunting noises by vibrating their swim bladders, particularly when startled or defending their territory.
Commonly Found At Dive Sites:
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White Rock (under ledges on the northern side)
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Hin Wong Bay (especially around boulders)
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Green Rock (inside swim-throughs)
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Red Rock / Nang Yuan Cave (good for night dives)
Conclusion
In this fifth part of our series, we’ve explored a mix of quirky, bold, and colorful marine life. From the tool-using Blacktip Tuskfish to the chatty Red Squirrelfish, Koh Tao’s reefs continue to amaze and delight, the fish are even more impressive in real life, so come dive Koh Tao with us see how much better they are than their AI counterparts above. Stay tuned for the next installment, where we’ll uncover even more incredible marine creatures waiting to be discovered! See more of our Koh Tao marine life in Part 6 of our Koh Tao Fish guide.