Pleuronectes is a marine bottom dweller in coastal waters lying on side. It feeds on molluscs. It swims by undulating movements. Indian water flat-fish is characterized by banded colouration.

GENERAL CHARACTERSTICS OF PLEURONECTES (FLAT FISH)

Commonly called as flat fish. Body divided into head, trunk and tail.
Fish is strongly compressed and asymmetrically flattened. Head is asymmetrical, the posterior cranium is normal but anterior cranium is twisted with two orbits on one side in the adult and hence the fish is sinistral. Eyes are found on left side. In some cases eyes can be dextral i.e., lying on right side. Nostrils also on left side.
Body scales are imbricate. Cycloid or ctenoid.
Mouth is narrow and protractile. It has sharp chisel-like teeth on the jaws and flattened crushing teeth in the pharynx.
Right side is white, left side is pigmented while lower side is silvery white.
The dorsal and anal fins are elongated, expanded and continue upto beginning of tail. Dorsal and anal fins supported by fin rays. Pectoral fins are placed high up and ventral fin below pectoral fin. Caudal fin fan shaped.
Air Bladder is physoclistous. Lateral line and operculum present spiracle absent.

SPECIAL FEATURES

Young Pleuronectes is bilaterally symmetrical, but adult fish is asymmetrical. It lies on one side and lower eye migrates around so that both eyes are on upper surface.