Oval shaped, compressed deep body. Small head, slightly concave in its upper profile. Small protractile slender mouth with rows of tightly-packed depressible teeth, forming brush-like surface. Interior teeth in both jaws are longer decreasing in length toward the posterior part of the jaws. Small gill rakers, 6-7 on the upper limb of the first arch and 13-14 on the lower limb. Small eye with wide space between them. Edge of preoperculum finely serrated. Long stout spine at lower angle of preoperculum. A single, long, based dorsal fin. Clear incisions between the first 4th to 5th spines, decreasing toward the soft rays portion which has no incisions. Caudal fin round. Deep incisions between anal fin spines. First ray of ventral fin often elongated. Body and head covered with small ctenoid scales.
color of adult: body and posterior portion of dorsal fin with diagonal alternating stripes of narrow yellow and wider bluish-purple. Black mask with bluish margin on the eye. Large black triangular area stretches from the pectoral fin base upward. Posterior dorsal fin and caudal are yellow. Anal fin grey to reddish-brown with blue stripes. Pectoral fin dark grey and pelvic fin dark-bluish grey with orange rays;
color of young specimens (up to 14 cm TL): body dark blue with white and blue vertical stripes on the head curving progressively and forming circles on the posterior half of the body.
size : common 10-30 cm (max. 40 cm).
The color pattern of this species differs significantly from all other Mediterranean species.
BIOLOGY / ECOLOGY
Live solitary or in pairs. Feeds mainly on sponges and algae. The male defends its territory aggressively; only after removal from the territory do the young fish change their color pattern and dominate the territory. Eggs and larvae pelagic.
habitat : among coral reefs and rocky habitats at depth of 5-60 m.