Hawaii's Reef Fishes

Soldierfishes and Squirrelfishes (Holocentridae)

Yellowstriped Squirrelfish Sargocentron ensifer (Jordan & Evermann, 1903)

The fishes of this family are spiny, red or partly red, with very large eyes. They have 11 or 12 (usually 11) dorsal spines, 4 anal spines, and the pelvic fins with 1 spine, 7 rays; the caudal fin is forked; the scales are coarsely ctenoid (their edges with numerous sharp spinules); the external bones of the head have ridges and grooves, some with small spines or serrate edges; the mouth is fairly large, but the teeth are small.

The family is divisible into two subfamilies, the Holocentrinae (squirrelfishes) with two Indo-Pacific genera (Neoniphon and Sargocentron), and the Myripristinae (soldierfishes) with four Indo-Pacific genera (Myripristis, Plectrypops, Pristilepis, and Ostichthys); the species of the last two genera occur in deep water.

The squirrelfishes are characterized by a long sharp spine at he corner of the preopercle, which may be venomous, and a somevhat pointed snout; the soldierfishes lack the spine on the preopercle or have a short broad-based one, and the snout is short and blunt.

Squirrelfishes and soldierfishes are nocturnal, as their large eyes suggest. They occur on reefs, tending to hide in caves or beneath ledges by day, coming out to forage for food at night. The squirrelfishes prey mainly on benthic crustaceans, whereas the soldierfishes feed on the larger animals of the zooplankton, such as crab larvae, often well above the bottom.

The general Hawaiian name for squirrelfishes is 'ala'ihi and of the soldierfishes. 'U'u (though the local name mempachi has largely replaced it).

Bigscale Soldierfish

Myripristis berndti (Jordan & Evermann, 1903) 'U'u

Outer part of spinous dorsal fin orange-yellow; white on leading edges of fins; 28-31 lateral-line scales; small scales in pectoral-fin axil; lower jaw projecting. Attains 11 inches (28 cm). East Africa to the tropical eastern Pacific; the most common soldierfish in Hawai'i in the depth range of 50-150 feet (15-46 m).

Brick Soldierfish

Myripristis amaena (Castelnau, 1873) 'U'u

Outer part of spinous dorsal fin red; no white on leading edges of fins; 32-36 lateral-line scales. Reaches 10.5 inches (26.5 cm). Appears to be confined to the islands of Oceania. Generally found inshore in less than 30 feet (9 m). M. argyromus Jordan & Evermann is a synonym.

Crown Squirrelfish

Sargocenfron diadems (Lacepede, 1801) 'ala'ihi

Red with narrow silvery white stripes on body; spinous dorsal fin deep red to nearly black with a disjunct whitish stripe in lower part; the two opercular spines about equal. Reported to 6.7 inches (17 cm), but rarely exceeds 5 inches (12.5 cm). Indo-Pacific; common in the depth range of 7-100 feet (2-30.5 m).

Yellowstriped Squirrelfish

Sargocentron ensifer (Jordan & Evermann, 1903) 'ala'ihi

Red with narrow yellow stripes dorsally and white stripes ventrally; spinous dorsal yellow with a red margin,the first spine about as long as second.To 10 inches (25 cm). Hawai'i, Japan, South China Sea, New Caledonia, and Pitcairn, usually at depths greater than 60 feet (18 m).

All information and pictures in this section are from John E. Randall's Shore Fishes of Hawai'i by permission of the author.