Belted Sandfish

Belted Sandfish, Serranus subligarius

Belted Sandfish, Serranus subligarius. Fish caught from coastal waters off Padre Island, Texas, November 2019, November 2019. Length: 10 cm (3.9 inches). Catch, photograph and identification courtesy of Eli (obsessiveangling.wordpress.com).

Belted Sandfish, Serranus subligarius. Fish caught off a jetty in Panama City, Florida, June 2023. Length:  12 cm (4.7 inches).  Catch, photograph and identification courtesy of Chris Moore, Peoria, Arizona.

The Belted Sandfish, Serranus subligarius, is a member of the Sea Bass or Serranidae Family, that is also known as the Dwarf Sea Bass and the Stubby Sea Bass and in Mexico as serrano aporreado. 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 Belted Sandfish has an elongated compressed body with a short head, a short pointed snout, and a short terminal mouth. Their head and body are a reddish-brown. Their body scales have dark spots that give the appearance of lines. They have a dark stripe through the eye that extends to mid-body. They have four dark bars that extend onto the dorsal fin with the first bar being very prominent, extending onto the front of the soft dorsal fin as a large black blotch. They have a white bar mid-belly. Their anal, caudal and dorsal fins have irregular thick brown bars and dark spots. Their pelvic fins are black with white front margins. They have 3 well-developed spines on their gill cover with the middle spine being and straight. Their anal fin has 3 spines and 7 rays; their caudal fin has a straight margin; their dorsal fin has 10 spines and 12 to 14 rays; their pectoral fins have 15 to 17 rays; and their pelvic fins are located in front of the pectoral fins. They have 15 to 19 gill rakers. They are covered with large rough scales.

The Belted Sandfish is a small species that is found within rocky structures and sand and rubble substrate with large amounts of silt, from surface to depths of 80 m (262 feet). They reach a maximum of 10.0 cm (3.9 inches) in length. They are generally a non-schooling solitary species that are nocturnal predators preying on small fish, small crustaceans and shrimp. They are known to practice cannibalism. The Belted Sandfish are synchronous hermaphrodites, with each fish having both ovaries that can produce eggs, and testes that can produce sperm. They have three different reproductive strategies: some  fish behave as females and are generally smaller fish; the majority of the large fish behave as males; some smaller fish, called streaker males, are opportunistic breeders. Although they have the ability to self-fertilize, cross fertilization is the usual reproductive mode. They have life spans of five years. The Belted Sandfish 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 Belted Sandfish is a resident of Mexican waters of the Atlantic Ocean but has a limited distribution, with three isolated populations being found. The first is just south of the United States boarder in Tamaulipas, the second off the coast of Veracruz, and the third on the Madagascar Reef on the Campeche Bank off the east coast of the Yucatán Peninsula.

The Belted Sandfish is very colorful with extensive markings that are a straightforward identification. They are similar to the Harlequin Bass, Serranus tigrinus (wide yellow line that runs from the tip of the snout to mid-body), the Pygmy Seabass, Serraniculus pumilio (broad white bar on caudal base; dorsal fin with 10 or 11 rays), and the Redspotted Hawkfish, Amblycirrhitus pinos (red spots covering head and dorsal fin).

From a conservation perspective the Belted Sandfish is currently considered to be of Least Concern with stable, widely distributed populations. Their populations are also being adversely affected by the recent introduction of the Red Lionfish, Pterois volitans, which competes for prey and space. In certain areas they are fairly common but due their small size they are of limited interest to most. They are utilized by the aquarium trade on a limited basis.