Blacktail Snailfish, Careproctus melanurus

Blacktail Snailfish, Careproctus melanurus. Fish caught off Point Loma, California, April 2008. Length: 24 cm (9.4 inches). Catch made by Eddie Kisfaludy, Scripps Institution of Oceanography, La Jolla, California. Identification courtesy of H.J. Walker, Jr., Scripps Institution of Oceanography, La Jolla, California.

The Blacktail Snailfish, Careproctus melanurus, is a member of the Snailfish or Liparidae Family, and is known in Mexico as baboso colinegra. The snailfish comprise a large and diverse family with three hundred thirty-four members that have been placed into twenty-nine genera. Globally, there are one hundred twenty-five species in the genus Careproctus.

The Blacktail Snailfish have soft, flabby, scaleless bodies with a tadpole-like head and anal and dorsal fins that are continuous with the caudal fin which tapers to a point at the rear. They have a fairly unique body shape with modified pelvic fins that form a small sucking disc placed far forward below the eyes. Their anus is also very far forward and almost directly under the eyes (pictured below). They are overall light pink in color with black anal and dorsal fins. Their caudal fin is long and has a black tip. The lining of their mouth, their gill cavity, and their tongue are black. Their anal fin has 37 to 50 rays; their caudal fin is slightly rounded; their dorsal fin has 54 to 58 rays; and, their pectoral fins have 6 rays initial rays that are thick and standalone, followed by 5 rays that are longer and less standalone. They  do not have a lateral line.

The Blacktail Snailfish are a bathydemersal species found in muddy bottoms at depths between 82 m (270 feet) and 2,135 m (7,000 feet). They reach a maximum of 54 cm (21 inches) in length and 1.7 kg (4 lbs 5 oz) in weight. They are bottom feeders and consume small clams, crustaceans, polychaete worms, and other invertebrates. They have a lifespan of up to 8 years. The Blacktail Snailfish 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 Blacktail Snailfish is a resident of Mexican waters of the Pacific Ocean but has a very limited distribution being found only from Ensenada, Baja California, northward along the northwest coast of Baja.

The Blacktail Snailfish is straightforward to identify due to its characteristic shape and cannot be confused with any other species.

The Blacktail Snailfish has not been formally evaluated from a conservation perspective. They are an abundant very deep water species but are seldom seen by humans. They are of limited interest to most.