Flathead are notable for their unusual body shape, upon which their hunting strategy is based. Flathead are dorsally compressed, meaning their body is wide but flattened and very low in height. Both eyes are on the top of the flattened head, giving excellent binocular vision to attack overhead prey. The effect is somewhat similar to flounder. In contrast to flounder however, flathead are much more elongated, the tail remains vertical, and the mouth is large, wide and symmetrical. Flathead use this body structure to hide in sand (their body colour changes to match their background), with only their eyes visible, and explode upwards and outwards to engulf small fish and prawns as they drift over the hidden flathead.
The dusky flathead can be distinguished from other flathead by a row of fine brown spots on the pectoral fins.