Rainbow Basslet, Liopropoma fasciatum

Rainbow Basslet, Liopropoma fasciatum. Fish caught from coastal waters off Point Palmilla, Baja California Sur, March 2016. Length: 16.5 cm (6.5 inches).

Rainbow Basslet, Liopropoma fasciatum. Fish caught from coastal waters off Puerto Los Cabos, Baja California Sur, February 2007. Length: 18.0 cm (7.1 inches). Identification courtesy of Dr. Ross Robertson, Smithsonian Tropical Research Institute, Panama.

Rainbow Basslet, Liopropoma fasciatum. Fish caught from coastal waters off Point Palmilla, Baja California Sur, October 2019.  Length: 25 cm (10 inches).

The Rainbow Basslet, Liopropoma fasciatum, is a member of the Grouper or Epinephelidae Family, and is known in Mexico as cabrilla arcoiris. Globally, there are twenty-seven species in the genus Liopropoma, of which six are found in Mexican waters, four in the Atlantic and two in the Pacific Ocean.

The Rainbow Basslet has an elongated body and a pointed head. They have a near horizontal profile with large eyes and a slightly upturned and very large mouth with a projecting lower jaw. Their head and belly are red and there are 4 horizontal stripes on their sides: a wide dark brown mid-lateral stripe, straddled by a strong yellow stripe above and a faint yellow stripe below, and a red-brown stripe just below the base of their dorsal fin (pictured above). Their anal fin has 3 spines and 8 rays; their caudal base has a very deep base which is greater than half the depth of the body and their caudal fin is round to slightly concave; their first dorsal fin has 8 spines, their second dorsal fin has 12 rays; and, their pectoral fins have 15 rays. They are covered with small rough scales.

The Rainbow Basslet is found in and around rocky and coral reefs at depths between 23 m (75 feet) and 229 m (750 feet). They reach a maximum of 33 cm (13 inches) in length and 450 grams (1 lb 0 oz) in weight. The Rainbow Basslet is a rare deep water species that 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 Rainbow Basslet is a resident of Mexican waters of the Pacific Ocean but has a limited distribution being only found in the lower two-thirds of the Sea of Cortez and along the coast of the mainland southward to Guatemala.

The Rainbow Basslet is straightforward to identify due to its unique coloration pattern. In body shape it is similar to the Scalyfin Basslet, Liopropoma longilepis, however, the latter lacks the mid-body banding.

From a conservation perspective the Rainbow Basslet is currently considered to be of Least Concern with stable, widely distributed populations. They are a rare catch by hook and line and too small to be of interest to most. They are however, a very colorful fish and one of the few bright oceanic fishes; as a result, they are sold extensively by the aquarium trade.