Body compr essed. Dor sal fin spineless. Ascaleless keel between vent and pelvic fins. A scalelessgroove on back, in front of dorsal fin. Mouth small butprotrusible. Males with tubercles. In lower parts of largerivers, lakes and ponds with dense vegetation. Toleratehigh temperatures of 34°C and a salinity of 13‰. Maximumage exceeds 20 years, total length 47 cm andweight 1.4 kg. Semi-migratory. Migration in spring andfall and spawning in April at temperatures of 19-24°C onweeds. Maturity at 2-3 years at total length of at least 23cm and weights of 600 g. Sex ratio 3Males:1female. Absolutefecundity up to 442,000 yellowish eggs of up to1.9 mm in diameter. Spawn repeatedly with differentpartners and mostly once a year, sometimes severaltimes. Food include zooplankton in young and invertebratesand detritus in adults.