Tongue soles are small flat-fishes (to 48 cm but usually < 20 cm) with elongate oval bodies that taper to a pointed tail; small close-set eyes on left side of the body; a small, curved, asymmetrical mouth; margin of preoperculum concealed by skin and scales; dorsal and anal fins confluent with the pointed caudal fin; only left pelvic fin present, 4 rays, on body midline, joined to anal fin by delicate membrane; pectoral fins absent, (represented by a fine membrane in Symphurus); no lateral line.
These fishes occur worldwide in tropical and subtropical seas (also a few species in freshwater). They are residents of flat soft bottoms, often sandy areas near reefs or more open stretches of mud, silt, or sand.
The family contains three genera and approximately 134 species. In our region there are 15 shallow-water species (all endemics) of one worldwide tropical to temperate genus.