Butterflyfish
Scientific name Chaetodon wiebeli
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 most common reef sightings. Many species form monogamous pairs and are often seen swimming closely together, maintaining small feeding territories. Their strong pair bonds are one of their most recognisable behaviours underwater.
Species such as the Threadfin Butterflyfish (Chaetodon auriga), Raccoon Butterflyfish (Chaetodon lunula) and Chevron Butterflyfish (Chaetodon trifascialis) each bring slightly different patterns and colours to the reef, but all share the classic butterflyfish shape and eye-mask marking that helps confuse predators.
Butterflyfish are considered important indicator species for reef health. Because many species feed directly on coral polyps, their presence often signals thriving coral growth and balanced reef ecosystems.
Their constant motion and intricate markings make them a favourite for relaxed reef dives and underwater photography.
Find Butterflyfish at...
Divemaster's tip
Look closely around branching corals and reef edges between 3–20 metres. Butterflyfish rarely stray far from coral cover.
If you spot one, scan nearby — its partner is usually close. Move slowly and avoid sudden movements to observe natural feeding behaviour.
What do they eat?
Butterflyfish primarily feed on coral polyps, small invertebrates and reef algae. Some species specialise in certain coral types, while others have more flexible diets.
Their grazing behaviour helps maintain reef balance, but also means they are sensitive to coral loss — making healthy coral systems essential for their survival around Koh Tao.
