Sea Chubs (Rudder Fishes)
By Ukkrit Satapoomin

Kyphosus vaigiensis

Medium-sized fishes (to 75 cm); body oblong or elliptical, moderately compressed. Head small; snout short with a low convexity above nostrils; mouth small and terminal. Single row of lanceolate incisor-like teeth on both jaws. First gill-arch with 5-10 gill rakers on lower limb, 14-24 on lower limb. Dorsal fin continuous, depressible in a sheath, with XI spines and 12-15 soft rays; anal fin with III spines and 11-14 soft rays; pectoral fins short, bluntly pointed posteriorly, with 16-20 rays; caudal fin more or less forked, with pointed lobes. Scales ctenoid, extending onto most of soft portions of dorsal and anal fins and onto caudal-fin base. Pored scales in lateral line 49-55. Color: dull olive or silvery black, lighter below; distinct longitudinal lines on sides.

Similar families occurring in the area. Sparidae: molar teeth often present; pectoral fins long. Lethrinidae: head much larger; lateral teeth conical or molar-like; pectoral fins long.

Remarks. Occur on rocky and coral reefs in tropical and temperate waters. Herbivorous, feeding primarily on benthic algae. Schooling, sometimes in a group of mixed species of other kyphosids.