Body deep and strongly compressed. Dorsal fin short, its spines increasing in size and the soft rays progressively decreasing. Anal fin very long, its length close to one-half of standard length. Eye very large. Short snout. Mouth oblique with slightly projected lower jaw which extend back to the vertical of the center of eye. Small teeth, some with tips incurved arranged in bands on jaws. Patches of villiform teeth on the palatine and vomar. Scales finely serrated. Lateral line gently curved, extending into caudal fin.
body brown bronze. Tip of dorsal fin black. Base of anal fin often black.
common 5-16 cm (max. 18 cm).
The body shape of this species differs significantly from all other Mediterranean species.
BIOLOGY / ECOLOGY
Nocturnal. During daytime, forms large schools hovering in caves. At dusk, they leave the caves to forage in the open water. At dawn, they retreat to their daytime refuge. Feeds chiefly on planktonic crustaceans and, to a lesser extent, on polychaets. Spawning season lasts from April to September (year-round in the Red Sea). Diameter of riped oocytes 0.5-0.7 mm. Eggs and larvae planktonic. Larvae transparent, have elongated body and settle in the rocky habitats at the size of 6-7 mm; active during daytime. Juveniles live in small groups of fish of similar size. Upon reaching 9 cm, they join adults schools.
day-time: caves and crevices, to depth of 20 m. At night: inshore pelagic.