Body shape : Elongated, slightly laterally compressed

Average size : 30 to 50 cm (12 to 20 in), 0.5 to 1.5 kg (1 to 3 lb)

Coloration :  Varies greatly according to habitat; markings paler in turbid water and more pronounced in clear water; body brown, olive, yellow or even gray or blue; flanks with scales having small golden spots; diffuse marbling on dorsal fin and large black spot on the edge; second dorsal fin and caudal fin with more-or-less regular rows of tiny specks; white spot on the edge of inferior lobe of caudal fin; pearlescent eyes due to a reflective pigment layer.

External characteristics : Large eyes; smooth cheeks with few scales; numerous sharp teeth; 2 distinct dorsal fins, the first with 12 to 16 spines and the second soft-rayed; anal fin with 2 spines; at least one small, sharp spine at the edge of the operculum.