Coralfish
Scientific name Chaetodontidae
“Coralfish” is a general term often used by divers to describe small, brightly coloured reef fish that live closely among coral structures — most commonly butterflyfish species. These fish are tightly linked to coral health and are rarely seen far from reef cover.
With flattened bodies and pointed snouts, coralfish are perfectly adapted for navigating tight coral branches. Many species have bold eye-stripes and intricate body patterns that help camouflage them among coral shadows and textures.
Around Koh Tao, they are frequently seen in pairs, gently fluttering from coral head to coral head while feeding. Their constant movement and strong attachment to specific territories make them reliable sightings on healthy reefs.
Because many coralfish feed directly on coral polyps, their populations can decline if coral reefs suffer from bleaching or damage. For this reason, they are often considered indicator species for reef condition.
Small, delicate and colourful, they represent the intimate connection between reef fish and coral ecosystems.
Find Coralfish at...
Divemaster's tip
Look closely at live coral heads between 3–20 metres. Coralfish rarely stray far from active coral growth.
If you observe one feeding repeatedly in the same area, chances are it’s defending a small territory — stay still and you’ll see natural behaviour.
What do they eat?
Most coralfish feed on coral polyps, small invertebrates and algae growing on coral surfaces.
Their specialised snouts allow them to pick precisely at coral tissue, making them highly dependent on thriving reef systems around Koh Tao.
