noun, plural (especially collectively) flat·fish, (especially referring to two or more kinds or species) flat·fish·es.
Examples from the Web for flatfish
We knew we'd no business to be there and we felt as foolish as flatfish.Lucy Maud Montgomery Short Stories, 1907 to 1908|Lucy Maud Montgomery
They breathed heavily through their noses and stared straight in front of them—impassive as flatfish.From Sea to Sea|Rudyard Kipling
There I was, caught in a trap, and made a prisoner by a flatfish.Peter Simple|Frederick Marryat
And thinkin' no more of it than I would of—of scalin' a flatfish.Galusha the Magnificent|Joseph C. Lincoln
Saint Petersburg is very ill supplied with salt-water fish; there are neither lobsters nor flatfish.Fred Markham in Russia|W. H. G. Kingston