Hawaii's Reef Fishes

Wrasses (Labridae)

Cheilio inermis (Forsskal, 1775) Kupoupou

The wrasses are a large and diverse family, varying greatly in size and shape. Typically they have thick lips, protruding front canine teeth, and nodular to molariform teeth in the pharyngeal region. The scales are cycloid (smooth-edged); the head is scaleless or with just the cheek and opercle scaled.

There is a single unnotched dorsal fin of 8-21 spines, and the anal fin usually has 3 spines. Most wrasses are brightly and complexly colored. Juveniles frequently have a very different color pattern from adults.

Sex reversal from female to male has been demonstrated for many wrasses and may be true of all species of the family. The change in sex is generally accompanied by a change in color pattern; the resulting terminal male is usually more vividly colored. Some terminal males, as well as juveniles, are so different in color that they were often named as different species.

Many species, such as those of the genera Stethojulis and Thalassoma, have identically colored mature males and females in the first color phase (termed the initial phase). These spawn in aggregations dominated by males. The release of eggs and sperm takes place at the peak of a rapid upward rush from the aggregation. Terminal males establish sexual territories and spawn individually with females in their harem.

Wrasses are diurnal; at night most of the smaller species bury in the sand to sleep; the larger ones hide deep within the reef. All wrasses are carnivorous; most, such as the species of Bodianus, Coris, and Thalassoma, feed on a variety of hard-shelled invertebrates such as crabs, hermit crabs, mollusks, sea urchins, and brittle stars which they crush with their powerful pharyngeal dentition.

Some of the larger wrasses such as Coris gaimard and Novaculichthys taeniourus turn over rocks to expose the invertebrates hiding beneath. The species of Anampses strike the bottom forcefully with their projecting teeth, sucking in very small animals such as crustaceans, Foraminifera, and mollusks, along with sand and debris; the species of Stethojulis do the same, but are more inclined to pick up sand.

A few wrasses feed mainly on fishes; some such as the species of Cirrhilabrus are zooplankton feeders; a few with very fleshy lips feed on coral polyps; and some such as those of the genus Labroides are cleaners or part-time cleaners (meaning they remove skin parasites and some mucus of other fishes).

Wrasses swim mainly with their pectoral fins, bringing their tails into action only when swift movement is needed. Most are closely associated with coral reefs or rocky substrata, but the razorfishes (Xyrichtys spp.) and knifefishes (Cymolutes spp.) live over open sand bottom. With their compressed bodies and thin foreheads, they are able to dive into sand to escape predation.

The Labridae is represented in Hawai'i by 43 species, more than any other shore fish family; some occur only at depths greater than penetrated by divers. The general Hawaiian name for most wrasses is hinalea; the small species usually have no specific Hawaiian name.

Hawaiian Hogfish