Silver y speckled with numer ous scatter edsmall black spots. Head dark. Fins greyish. Pectoral finsextend past origin of pelvic fins. Scales rounded ovalwith a slightly posterior focus. Pharyngeal teeth withsmooth grinding surfaces. Gut elongate and convoluted.Males with a sharp edge along dorsal surface of severalanterior pectoral fin rays. Elongate and compressedbody. Eyes low on head with their lower margin belowmouth corner level. No barbels. Branchiostegal membranesjoined and free of isthmus. Weak dorsal and analunbranched rays. A ventral keel from pelvic fin to anus.In large rivers and associated floodplains. Tolerate salinitiesup to12‰ and prefers temperatures of 20-30°C.Maximum age 16 years, total length 146 cm and weight50 kg. Maturity at 2-5 years. Migration to rivers in secondweek of May at 18-19°C. Spawning after a sharprise in water level and current. No report on its naturalreproduction in Iran. Absolute fecundity up to 1,860,000eggs of 1.5 mm in diameter. Food almost exclusivelyzooplankton, when zooplankton biomass low, phytoplanktonand detritus.