Bathylagoides wesethi very low on the underside of the body. The colour is dark brown above with black spots and a black patch around the operculum, which extends halfway up the body. The flanks are silvery-grey and the fins lack pigment. The caudal peduncle is narrow, the caudal fin is short, and the lateral line, which is high on the body, extends into the tail fin. The maximum length to which this fish grows is about . The snubnose blacksmelt is found in deep water in the Pacific Ocean off the western coast of North America. Its range extends from 45°N to
Copella (genus) observation. The pectoral fins are positioned immediately behind the operculum or gill cover, while the pelvic fins are further back along the body, about midway between the head and the caudal peduncle. The dorsal fin is positioned above and slightly behind the pelvic fins, and midway between the pelvic fins and the tail fin is the anal fin. The tail fin is forked in shape. Males usually possess more elongated and ornate unpaired fins than females. In the case of "C. arnoldi", the tail fin of the male is somewhat asymmetrical, the upper lobe being larger than the lower lobe,