Sweetlips are large, slow-moving reef fish known for their thick, fleshy lips and striking patterns. Around Koh Tao, the Harlequin Sweetlips and Oriental Sweetlips are the most recognisable species. Adults often rest in small groups beneath overhangs, inside caves or along sheltered reef slopes between 8–25...
Bannerfish are elegant, high-contrast reef fish instantly recognised by their bold black-and-white bands, yellow highlights and long trailing dorsal filament that waves like a banner in the current. Around Koh Tao, they are commonly seen in pairs or small schools hovering above coral slopes and pinnacles....
Angelfish are among the most colourful and elegant residents of the reef. With their laterally compressed bodies, extended dorsal and anal fins, and striking colour patterns, they bring movement and vibrancy to Koh Tao’s coral gardens. Two of the most recognisable species locally are the Blue...
Butterflyfish are small, brightly coloured reef fish known for their delicate patterns, bold eye stripes and constant, fluttering movement among coral heads. Their laterally compressed bodies allow them to slip easily between branches and crevices as they search for food. Around Koh Tao, butterflyfish are among...
The Honeycomb grouper, also known as a Hexagon grouper, is found throughout the tropical and subtropical Indo-Pacific. It lives in sheltered reefs and shallow lagoons to a depths of a maximum of 50 meters, but not usually below 20 meters. Divemaster’s Tip: Don’t expect to always find these guys swimming...
Goatfish are easily recognised by the pair of sensory barbels (whisker-like feelers) under their chin. These barbels are packed with chemoreceptors, allowing them to detect hidden prey in sand and rubble — giving them their distinctive, constantly “searching” behaviour. Around Koh Tao, goatfish are common on...
The Red-Breasted Wrasse is a bold and beautifully patterned member of the wrasse family, commonly seen cruising along Koh Tao’s reef slopes. Recognisable by its reddish to orange breast and striped body pattern, it has a confident presence without the enormous size of its cousin, the Humphead...
Damselfish are small, colourful and incredibly common reef fish found throughout tropical oceans. Despite their size, they are famously bold and highly territorial. Around Koh Tao, you’ll see damselfish in almost every shallow reef zone from 2–20 metres. Many species are electric blue, yellow or striped,...
The Sergeant Major is one of the most recognisable and abundant reef fish around Koh Tao. Instantly identifiable by its bold black vertical stripes against a pale silver or yellow body, its pattern resembles military insignia — giving rise to its name. Usually growing to around...
