Calves are light to dark gray dorsally and white ventrally. The fin whale is brownish to dark or light gray dorsally and white ventrally. These fish are dark bluish-green dorsally and silvery white ventrally. This species exhibits countershading, with brilliant metallic blue coloration dorsally and white ventrally. Both sexes are generally a reddish-brown dorsally and colored a dirty cream ventrally. It is dark-colored dorsally and yellow-green ventrally. Simultaneously, the stomach begins to expand in width dorsally and ventrally in an asymmetric manner. This family is both dorsally and ventrally covered in knob-like scales. The chartaceous or sometimes coriaceous lemmas have somewhat dorsally rounded and distally keeled bases. The rostral scale is projecting, upturned, recurved and keeled dorsally. These crossbands have vague borders and are wider dorsally than laterally. Thorax dorsally with a yellow patch between wing bases. The carapace is flattened dorsally and highest anterior to the bridge. The ulna continues growing straight, resulting in a dorsally prominent distal ulna. The pigment cup is oriented concave dorsally.