Hardtail Conger, Gnathophis cinctus

Hardtail Conger Eel, Gnathophis cinctus. Fish provided by the commercial fishermen of the Greater Los Cabos area, Baja California Sur, July 2012. Length: 13.4 cm (5.3 inches); tail 52% of TL.

The Hardtail Conger, Gnathophis cinctus, is a member of the Conger Eel or Congridae or Family, and is known in Mexico as congrio cola tiesa. Globally, there are twenty-five species in the genus Gnathophis, two of which are found in Mexican waters, one in the Atlantic and one in the Pacific Ocean.

The Hardtail Conger has an elongated narrow “eel-like” body. They are uniform pale gray-brown in color with a silvery mid-section. Their head is pointed with disproportionately large eyes set well on the back in their head, a horizontal mouth with bands of simple conical teeth, and an overhanging long snout that has a keel ventrally. Their anal and dorsal fins are continuous with their caudal fin; their caudal fin has a small stiff tip (after which they are named); their dorsal fin origin is over the rear of their pectoral fins; and, their pectoral fins are well-developed and end above their gill cover openings. A key to identification is their tail length which is reported to be greater than 60% of total length, however, I note that the small fish pictured above has a tail length of only 52%. They have a complete lateral line.

The Hardtail Conger is a demersal species found buried within coastal sandy substrates at depths between 10 m (33 feet) and 366 m (1,200 feet). They reach a maximum length of 42 cm (17 inches). The Hardtail Conger is rare, seldom seen by humans and is poorly studied with very limited information available about their lifestyle and behavioral patterns, including specific details on age, growth, longevity, movement patterns, diet, habitat use, and reproduction.

The Hardtail Conger is a resident of all waters of all Mexican waters of the Pacific with the exception that they are absent from the extreme northern portions of the Sea of Cortez.

The Hardtail Conger is most likely confused with the Needletail Conger, Rhynchoconger nitens (small beady black eyes).

From a conservation perspective the Hardtail Conger is currently considered to be of Least Concern with stable, widely distributed populations. They are small in stature, exceedingly rare, and of limited interests to most.