Squirrelfish, Holocentrus adscensionis

Squirrelfish, Holocentrus adscensionis, Juvenile. Fish caught from coastal waters off Long Island, New York, September 2023. Length: 6.6 cm (2.6 inches). Catch, photograph and identification courtesy of Aidan Perkins, Long Island, New York. Note: this catch documents a northerly range extension for this species as historically it was believed to only extend as far north as the Chesapeake Bay.

Squirrelfish, Holocentrus adscensionis. Fish caught out from coastal waters of the Cayman Islands, July 2016. Length: 25 cm (9.8 inches). Catch, photograph and identification courtesy of Ryan Crutchfield, Tampa, Florida.

Squirrelfish, Holocentrus adscensionis. Fish caught off a coastal pier in Key Largo, Florida, December 2013. Length: 14.8 cm (5.8 inches). Catch, photograph and identification courtesy of Ben Cantrell, Peoria, Illinois.

Squirrelfish, Holocentrus adscensionis. Fish caught off a coastal pier in Key Largo, Florida, April 2019. Length: 14.8 cm (5.8 inches). Catch, photograph and identification courtesy of Luke Ovgard, Klamath Falls, Oregon.

Squirrelfish, Holocentrus adscensionis. Fish caught from coastal waters off San Juan, Puerto Rico, December 2013. Length: 14.8 cm (5.8 inches). Catch, photograph, and identification courtesy of Josh Leisen (joshadventures.com), Gaylord, Michigan.

Squirrelfish, Holocentrus adscensionis. Underwater photograph taken in coastal waters off Bonaire, December 2019. Photography and identification courtesy of Bob Hillis, Ivins, Utah.

The Squirrelfish, Holocentrus adscensionis, is a member of the Squirrelfish or Holocentridae Family, that is also known as the Common Squirrelfish and in Mexico as candil de vidrio. Globally, there are two species in the genus Holocentrus, both found in Mexican waters of the Atlantic Ocean.

The Squirrelfish has a oblong fusiform compressed perch-like bodies with a depth that is 29% to 31% of standard length. They are pink on their upper head and body and white ventrally. They have light silvery stripes that follow the scales rows and a white streak extending diagonally across their cheeks. Some fish have a white blotch at the rear. Their spiny dorsal fin is yellowish with white blotches between the tips. Their anal, caudal, soft dorsal, pectoral, and pelvic fins are pinkish-white. Their caudal fin base is white. They have a pointed head, very large eyes with red pupils, and a large mouth that opens in the front and extends to the middle of the eyes. They are equipped with small villiform teeth found on the jaws and roof of the mouth. The corner of their gill cover has a large long spine. Their anal fin has 3 or 4 spines and 10 rays; their caudal fin is deeply forked with an elongated upper lobe and pointed tips; and their dorsal fin is continuous with 11 spines and 14 to 16 rays with the ray portion being elongated. They have 15 to 18 gill rakers. Their body is covered with large rough scales that give them a sandpaper-like feel. Their lateral line is complete.

The Squirrelfish are found from the surge zone to depths up to 245 m (800 feet). Adults are solitary individuals found in and around shallow coral reefs as well as in deeper waters whereas juveniles are found in small aggregations. They reach a maximum of 61 cm (2 feet 0 inches) in length. They are nocturnal and feed primarily on meroplankton (crab larvae and shrimp larvae), small crustaceans, and fish. They hide in small caves within rock structures to avoid predation during daylight hours. They are preyed upon primarily by Dorado, Longlure Frogfish, Mutton Snapper, and Yellowfin Tuna along with various sea birds. Reproduction is believed to involve batch spawning, with each female releasing 50,000 to 250,000 eggs in open water and pelagic eggs and larvae settling out in several weeks. They have the ability to produce sound via their swim bladder, which is believed to be used for intra-species communications. The Squirrelfish 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 Squirrelfish is a resident of all Mexican waters of the Atlantic including the Gulf of Mexico and the Caribbean.

The Squirrelfish is most likely confused with the Longspine Squirrelfish, Holocentrus rufus (a uniformly colored dorsal fin with white triangular spots at the upper margin).

From a conservation perspective the Squirrelfish is currently considered to be of Least Concern with stable, widely distributed populations. They are easily caught via handlines, gill nets, and traps. Although small in stature they are considered an excellent food fish and are a mainstay in the diet of subsistence fishermen. They are marketed fresh on a limited basis in some countries of South America. They are also popular fish in public aquariums because of their availability, bright red color, large eyes, and hardiness.