Harlequin Bass, Serranus tigrinis

Harlequin Bass, Serranus tigrinis. Underwater photograph take in coastal waters off Bonaire, December 2019. Photography courtesy of Bob Hillis, Ivins, Utah.

The Harlequin Bass, Serranus tigrinis, is a member of the Sea Bass or Serranidae Family, and is known in Mexico as serrano arlequín. Globally, there are twenty-seven species in the genus Serranus, of which thirteen are found in Mexican waters, ten in the Atlantic and three in the Pacific Ocean.

The Harlequin Bass has an elongated moderately compressed body that has a short head, a long pointed snout, a small terminal mouth and 3 prominent spines on the gill cover. Their head and body are white dorsally and yellowish ventrally. They have a black stripe that runs from the front of the snout and through the eye. They have large black blotches on the lower head and throat, 2 black bars at the rear of the head and 6 black bars on the body. Their anal fin has a row of black spots along its base; their caudal fin as a black bar at its base with the balance of the fin being covered with black spots; and, their dorsal fin has two rows of black spots. Their anal fin has 3 spines and 13 to 15 rays; their caudal fin is slightly concave; their dorsal fin has 10 spines and 12 rays; their pectoral fins have 13 to 15 rays; and, their pelvic fins are inserted before the pectoral fin base. They have 15 to 19 gill rakers. They are covered with large rough scales.

The Harlequin Bass is found in clear water within rocky structure and scattered corals at depths up to 55 m (180 feet). They reach a maximum length of 29 cm (11.4 inches). They are generally found as a solitary species or in pairs and feed on crustaceans. Reproduction involves protogynous hermaphrodites that are capable of changing from female to male as needed, with pelagic eggs and larvae. The Harlequin Bass 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 Harlequin Bass is found in all Mexican waters of the Atlantic with the exception that they are absent from the Gulf of Mexico north of Veracruz and along the east coast of the Yucatán Peninsula in the Caribbean.

The Harlequin Bass, due to its unique markings, is a straightforward identification. They are similar in size and shape to the Chalk Bass, Serranus tortugarum, the Crosshatch Bass, Serranus luciopercanus, and the Lantern Bass, Serranus baldwini, both of which are also heavily mottled in various shades of black, red, white, and yellow.

From a conservation perspective the Harlequin Bass is currently considered to be of Least Concern with stable widely distributed populations. They are fairly common, but due to their small size and location in very deep waters, they are of limited interest to most. They are utilized by the aquarium trade at a modest level being very easy to maintain.