Black plaice  (scientific name: Parastromateus niger) is a species of sea fish in the Starfish family, native to coral reef areas in the Indian Ocean and western Pacific Ocean. They live at a depth of 15–105 m (49–344 ft) in coastal areas with muddy bottoms, although they are rarely found to depths above 40 m (130 ft) and sometimes also enter estuaries. They operate near the bottom during the day and at night float near the surface. This fish plays a very important role in regional fisheries. It is also the only species to be classified in the genus Parastromateus .
This fish can reach up to 75 cm (30 inches) long, has a very tall diamond shape and flattens the sides. The head is large and the height is greater than the length, the mouth is round and obtuse. Small mouth at front of head, slightly slanting. The teeth are sharp and small, one row and very sparse. Sugarcane leaf bone, gnarled and on the tongue without teeth.
Dorsal ‐ fin spines: 2 – 6; soft rays of dorsal fin: 41-46; anal fin spines: 2; soft rays of anal fin: 35 – 40; vertebrae: 24. Deep stem and strong compaction. Lateral line terminating in underdeveloped scales on caudal peduncle. Pelvic fins disappear in large individuals over 9 cm. Brown above, silvery white below. The anterior parts of dorsal and anal fins are blue-gray. The other fins are yellowish. 
Often forming large flocks. Food: small shrimp, plankton and small benthic.
Being a fish with high economic value, exploited mainly by gill nets. Distribution zone: in the Gulf of Tonkin, Central and Eastern waters, southwest of the South. The harvest season is all year round so it is very suitable for the fishery. Fish live in the middle and bottom layers, spawning season from April to June.