Back br own or olive-green to black. Upperflanks light to dark brown. Belly and lower flank yellowto white. Fins reddish-brown. Iris golden to orange. Peritoneumblack. Last dorsal fin unbranched ray thickenedand serrated. Mouth slightly arched or straight in ventralview. A pelvic fin axillary scale present. Hornyedge to lower jaw usually well-developed. Gill rakersthick, usually hooked at tips and short, reaching past thefirst or second raker when appressed. Gut very elongatewith numerous anterior and posterior coils. Males withlarge tubercles on anal fin rays. In habitats with temperaturesup to 28°C, EC up to 2,125 and pH=7.9-8.7.Maximum total length 35 cm. Maturity in males at 2-4years and in females at 3-4 years. Spawning in latespring and summer. Egg 1.5 mm in diameter. Food includefilamentous algae, plant fragments, diatoms andinsects