Back olive-green to dark green. Flank lighterand with 5 dark blotches. Belly cream to white. Head andbody darkly spotted. Fins with thin bars as rows of spots.Pectoral fin yellowish-green with a dark spot on its base.Peritoneum silvery with a few scattered melanophores.Head scales mostly cycloid but body scales ctenoid. Gillrakers short and reach one below when appressed. Gutshort and S-shaped. Males larger, brighter, their dorsalfins longer and body size larger than females. On sandand mud substrates, but prefers rocks and lies embeddedin sand with only eyes protruding and rarely swim freely.Young fish may form schools in shallow waters. Prefertemperatures of 22-25°C and pH=6.5-7.2. Maximum totallength about 50 cm. Eggs green, 0.5 mm in diameterand when laid attach to submerged structures by a shorttube. Freshwater populations may migrate to sea to breedmarine larvae, although some land-locked and freshwaterbreeders. Spawning period June-September, peaking inJuly-August. Food include small fishes and crustacean.