This is the first in a multipart blog series exploring the vibrant and diverse marine life around Koh Tao. Each post will dive into a selection of fascinating fish, rays, turtles, and more, showcasing their unique traits, how common they are, and why they make diving here unforgettable. Stay tuned for future installments as we cover even more underwater wonders of Koh Tao!
Blue-Ringed Angelfish 
About: The Blue-Ringed Angelfish is a dazzling sight on Koh Tao’s reefs, with electric blue rings glowing against a rich orange body. These beauties are usually spotted near coral formations and often in pairs. Shy and elusive, they prefer to keep a little distance, so slow and steady approaches are key to observing them up close.
How Common? Fairly common, but patience is needed to find them during your dives.
Fun Fact: Blue-Ringed Angelfish are known to make “grunting” sounds when they feel threatened—nature’s very own underwater warning system!
Chevron Barracuda
About: The Chevron Barracuda is a sleek and striking predator, often found schooling in deeper waters or patrolling coral drop-offs. With their reflective silver scales and toothy grins, they’re a sight to behold—though they’re far less menacing than they look.
How Common? Common, especially in open-water areas. Divers frequently spot large schools of Chevron Barracudas around Koh Tao.
Fun Fact: Chevron Barracudas can grow up to 1.5 meters long and are incredibly fast swimmers, capable of short bursts of speed to catch prey.
Pink Anemonefish
About: Easily one of the cutest residents of Koh Tao, the Pink Anemonefish hangs out in symbiotic relationships with sea anemones. Their soft pink hue with a white stripe makes them easy to spot. These social fish live in groups, with the largest—and bossiest—always being female.
How Common? Very common around coral reefs with anemones.
Fun Fact: All anemonefish are born male, and the largest in the group transforms into a female if the dominant female is removed. Talk about climbing the corporate ladder!
Great Barracuda
About: The Great Barracuda is the big sibling of the Chevron, known for its imposing size and solitary nature. You might find one hovering near reefs or lurking in the blue, watching divers with curious intent.
How Common? Less common than the Chevron Barracuda but still frequently spotted on deeper dives.
Fun Fact: Great Barracudas’ reflective scales act like mirrors, helping them blend into their surroundings and evade predators.
Titan Triggerfish
About: The Titan Triggerfish is a bold and often territorial character, known for its vibrant yellow and gray coloration and large size. While generally docile, they can be feisty when guarding their nests, so give them space!
How Common? Very common and almost guaranteed to be seen on dives around Koh Tao.
Fun Fact: Their powerful jaws can crunch through coral, which is a key part of their diet.
Bluespotted Ribbontail Ray
About: A true treasure of the ocean floor, the Bluespotted Ribbontail Ray is a small, graceful species with vivid blue spots decorating its back. They’re often found hiding under sandy overhangs or resting on the seabed.
How Common? Fairly common but requires a sharp eye to spot as they blend into the sand.
Fun Fact: The bright blue spots serve as a warning to potential predators: these rays pack venom in their tails!
Crown of Thorns Starfish
About: The Crown of Thorns Starfish might look like a villain from a sci-fi movie with its spiky exterior, but it plays a crucial role in maintaining coral reef balance. These nocturnal creatures are coral predators, helping prevent overgrowth.
How Common? Occasionally seen, particularly during night dives.
Fun Fact: Despite their spiky appearance, Crown of Thorns Starfish can regenerate lost arms, making them resilient reef dwellers.
Whale Shark
About: The ultimate bucket-list sighting for divers, the Whale Shark is the gentle giant of the sea. These massive filter feeders glide gracefully through the waters, often drawing crowds of divers lucky enough to spot one.
How Common? Rare, but sightings spike during certain months. They’re often seen around deeper dive sites like Chumphon Pinnacle.
Fun Fact: Whale Sharks can grow over 12 meters long, making them the largest fish in the world—and they’re harmless to humans!
Green Sea Turtle
About: Graceful and ancient, Green Sea Turtles are frequent visitors to Koh Tao’s reefs. They can often be seen munching on seagrass or cruising along coral gardens.
How Common? Relatively common, especially at dive sites like Ao Leuk and Hin Ngam.
Fun Fact: Green Sea Turtles can live up to 80 years and hold their breath for several hours while resting.
Conclusion
Diving around Koh Tao offers an incredible opportunity to encounter a diverse range of marine life. From the shimmering scales of barracudas to the playful antics of anemonefish, each dive brings a new adventure. At Chalok Reef Divers, we’re here to guide you through these underwater wonders, ensuring every moment is unforgettable.
Stay tuned for the next part of our series as we explore even more fascinating marine creatures of Koh Tao!