Arabian trunkfish
A small boxfish found only in the Red Sea, the Gulf of Aden, the Arabian Gulf and Oman. Males are blue on the sides and tail with black spots and an olive-yellow back; females are yellowish with black spots.
The Arabian trunkfish, also known as the bluetail trunkfish, is a small boxfish with one of the most restricted ranges in its family. It is found only in the Red Sea, the Gulf of Aden and the Arabian Gulf, and along the coast of Oman between them. Like other boxfishes it is enclosed in a rigid case of fused bony plates, square in cross-section, from which only the fins, the tail, the eyes and the small protruding mouth can move. It swims by sculling with the dorsal, anal and pectoral fins and uses the tail mainly for steering and for sudden bursts.
The sexes differ in colour. The male is blue on the sides and on the tail, the blue scattered with small black spots, and the top of the carapace is olive to yellowish brown. Females and young fish are yellowish to greenish, also with black spots, and lack the blue sides. The yellow boxfish, which shares its reefs, grows much larger, and its young are bright yellow with black spots and have no blue on them.
It lives alone on coral reefs from a few metres to about 25 metres, staying close to the coral and moving slowly between overhangs and gaps in the reef. It feeds on small invertebrates and algae picked from the bottom. It is a shy fish that tends to turn away and put coral between itself and a diver, and patience usually produces a better view than pursuit. Boxfishes can release a toxin from the skin when badly stressed, which matters in an aquarium and not on the reef.
Where to find:
Ratings are per location: 1 means found on most dives that look for it, 5 means a handful of records. Where enough dives have been logged the figure is calculated from them; otherwise it is an editorial estimate, and says so. We publish habitat and destination, not the dive site.