Yellow boxfish – a yellow fantasy under the blue Ocean.

The Yellow boxfish (Ostracion cubicus) is a genus of Ostracion. This yellow species also known as Blue-spotted Box-fish, Cubed Boxfish, Cubical Boxfish, Polka Dot Boxfish and Yellow Trunkfish. The Yellow Boxfish inhabits coral and rocky reefs, and it is found at depths of 1 m to 40 m.

It can be recognized by its box-shaped body, bright yellow colouration and black spots. Juveniles have black spots about the size of the pupil. As it ages, the brightness fades and very old specimens will have blue-grey coloration with the faded yellow, sometimes even changing to white spots with a black margin. It feeds mainly on algae, but will also feed on sponges, crustaceans and mollusks. It reaches a maximum length of 45 centimeters (18 in).

The species occurs in tropical and temperate marine waters of the Indo-West Pacific (Pacific Ocean and Indian Ocean), including Indonesia, New Guinea, north to the Philippine Islands and east to Fiji and French Polynesia as well as the south eastern Atlantic Ocean. In Australia the Yellow Boxfish is known from the central coast of Western Australia around the tropical north and down the east coast to south of Sydney, New South Wales.