Fivefinger Razorfish

Iniistius pentadactylus, commonly known as the fivefinger wrasse or fivefinger razorfish, is a marine ray-finned fish belonging to the Labridae family, with a broad distribution across the Indo-Pacific region.

Physical Description

Iniistius pentadactylus presents a pale-grey coloration adorned with several overlapping red spots along the lateral line to the rear of the head, which appear black underwater. A brown blotch is often observed immediately posterior to the tip of the pectoral fin. While females lack these spots along the lateral line, they exhibit a prominent white area with red scale margins on the lower flanks. Members of the genus Iniistius are characterized by notably compressed bodies and a steep forehead with a hard, knife-like edge. This anatomical feature facilitates their ability to swiftly dive into sand when threatened, a behavior that contributes to their common name, razorfish. The species is equipped with nine spines in its dorsal fin, of which the first two are distinctly separated from the others by a notch. Additionally, the dorsal fin contains 12 soft rays, whereas the anal fin comprises 3 spines and 12-13 soft rays. The largest males can reach a total length of 25 centimeters (9.8 inches).

Distribution

The geographical range of Iniistius pentadactylus encompasses the eastern coast of Africa, from the 🌊 Red Sea extending south to 🇲🇿 Mozambique, and eastward to 🇬🇺 Guam. In the Pacific, its distribution stretches as far north as the Ryukyus and the Ogasawara Islands, and south to include the Great Barrier Reef and Christmas Island in 🇦🇺 Australia.

Habitat and Behavior

Iniistius pentadactylus typically inhabits sandy substrates in coastal areas, as well as regions with sea grass or algae, and is commonly found at depths exceeding 18 meters (59 feet). This species is predominantly observed in large, dispersed groups along the upper slopes of sand and mud banks. Males are territorial, overseeing territories that encompass multiple females. The species employs a unique behavioral adaptation for safety during rest; it buries itself in sand to sleep securely at night. When threatened, the fish dives head-first into the sand, a concealment tactic that may result in a delayed emergence. Its diet primarily consists of hard-shelled invertebrates, including molluscs and crustaceans.