Cuttlefish
Scientific name Sepia
Cuttlefish are highly intelligent cephalopods closely related to octopus and squid. They have a broad, oval body with a thin fin running along the sides, large expressive eyes, and eight arms plus two longer feeding tentacles.
Masters of camouflage, cuttlefish can change colour, pattern and even skin texture in seconds. They use specialised pigment cells to blend into coral, sand or rock — or to flash bold patterns during communication and courtship.
Around Koh Tao, they are usually found hovering over sandy patches, rubble areas or near coral reefs between 5–25 metres. They move with graceful undulating fin motions, appearing to float effortlessly through the water.
When threatened, cuttlefish may release a cloud of ink and rapidly change colour before jetting away. Despite this dramatic defence, they are generally calm and fascinating to observe.
Find Cuttlefish at...
Divemaster's tip
Watch carefully for subtle movement or unusual textures on sand or reef — what looks like rock may suddenly ripple and change colour.
Avoid cornering them. If stressed, they may turn pale or dark rapidly — a sign to give them space.
What do they eat?
Cuttlefish are active hunters, feeding on small fish, crabs and shrimp.
They use their two extendable tentacles to rapidly snatch prey, often stunning it first with a burst of colour patterning before striking.
