Twotone tang

Distributed across the Indo-Pacific. In Japan, in coral reef areas from Suruga Bay southwards. Reaches 20 cm in length.  Its dorsal fin and anal fin are long, similar to the sailfin tang (Zebrasoma velifer) and the yellow tang (Zebrasoma flavescens). It is a deep bodied fish. There are various body colors from black to yellow. Yellow twotone tangs are hard to differentiate from a yellow tang. A white spine is located on each side of the base of the tail fin which is unique to the family Acanthuridae. Usually these spines are laid flat against the surface of its body. They feed on seaweeds on the surface of bedrocks. They are often seen picking at the surface of walls in “The Sea of Tropical Fish” tank.