Glasseye

Overview

The Glasseye (Heteropriacanthus cruentatus) is a distinctive, nocturnal marine fish widely distributed across tropical and subtropical waters. Known for its large, reflective eyes, this species is typically found in association with coral reefs and rocky substrates, where it often seeks shelter in caves or under ledges during the day.

Distribution & habitat

This species has a broad, circumtropical distribution, inhabiting the Atlantic, Indian, and Pacific Oceans, though it is notably absent from the Red Sea. It is primarily an insular species, favoring shallow lagoon and seaward reef environments. While adults are typically reef-associated, juveniles are pelagic and can be transported by currents into more temperate regions.

Appearance

The Glasseye is characterized by a nearly symmetrical body profile and a rounded caudal fin. Its coloration is highly variable, ranging from a solid, vibrant red to a mottled pattern of red and silver, which the fish can change rapidly. The median fins often feature faint dark spots, and the pelvic fins are positioned well forward of the pectoral fins, attached to the belly by a membrane.

Biology & behavior

Primarily nocturnal, the Glasseye is often solitary during the day, resting in protected crevices. However, it may gather in larger numbers at dusk. It is known to produce sound and is considered a benthopelagic species. While generally harmless, there are reports of ciguatera poisoning associated with its consumption in some regions.