Appearance
E. naucrates is a medium-sized fish which can grow up to 110 cm (43 in) length. Its body is elongated and streamlined, and its lower jaw is clearly prognathic (it projects forward well beyond the upper jaw). The jaws, vomer and tongue have villiform teeth.
The main distinctive feature to distinguish from other fishes is the oval-shaped sucking disc, which is a highly modified dorsal fin positioned from the top of the head to the anterior part of the body.
The body background colouration is dark grey to dark brown, with a dark belly. A longitudinal stripe runs along the axis side of the body, it is always darker than its background colour with a whitish margin.
The caudal fin is black with white corners.

