Bridled Parrotfish
Bridled Parrotfish
© François Libert
Fishes · Bony fishes · Parrotfishes

Bridled Parrotfish

Scarus frenatus Lacepède, 1802
syn. Callyodon frenatus, Callyodon sexvittatus, Callyodon upolensis, Callyodon vermiculatus, Scarus randalli, Scarus sexvittatus +1 more
47 cm1-25 mLeast Concern
908

Scarus frenatus, commonly known as the bridled undefined or the six-banded undefined, is an intriguing species characterized by its vibrant color patterns and key role in marine ecosystems. This undefined can grow up to 47 cm in length and undergoes notable changes in appearance throughout its life. In its early stages, it exhibits a reddish-brown hue with six to seven dark horizontal stripes and red fins. As males mature, the back of their bodies and the lower half of their heads transform to a lighter shade, and their caudal fins display a striking blue-green color accented with a large, orange crescent shape.

The natural habitat of Scarus frenatus spans the vast Indo-Pacific region, stretching from the 🌊 Red Sea to the Line Islands and Ducie Island. Its range extends northward to southern 🇯🇵 Japan and southward to places like Shark Bay in Western Australia, Lord Howe Island, and Rapa Iti in 🇵🇫 French Polynesia, though it is notably absent from Hawaiian waters.

Typically found at depths ranging from 1 to 25 meters, the bridled undefined prefers exposed outer reefs but can occasionally be seen in extremely shallow waters. Juvenile fish often inhabit lagoon areas, living among the rubble and coral of the reefs. Generally, these fish are solitary, although they may join schools with other species while feeding. Scarus frenatus primarily grazes on algae in the benthic zone, playing a crucial role in maintaining the health of coral reef ecosystems by controlling algae growth. Through their feeding habits, these undefined contribute significantly to the ecological balance of their marine environment.

Why it's threatened

Biological resource use
Intentional use: (subsistence/small scale) [harvest]

This species is fished in some parts of its range where destructive fishing practices and habitat destruction are prevalent. However, these threats are not considered to affect the overall status of its population.

Parrotfishes show varying degrees of habitat preference and utilization of coral reef habitats, with some species spending the majority of their life stages on coral reefs, while others primarily utilize seagrass beds, mangroves, algal beds, and /or rocky reefs. Although the majority of the parrotfishes occur in mixed habitat (primarily inhabiting seagrass beds, mangroves, and rocky reefs) approximately 78% of these mixed habitat species are experiencing greater than 30% loss of coral reef area and habitat quality across their distributions. Of those species that occur exclusively in coral reef habitat, more than 80% are experiencing a greater than 30% of coral reef loss and degradation across their distributions. However, more research is needed to understand the long-term effects of habitat loss and degradation on these species populations. Widespread coral reef loss and declining habitat conditions are particularly worrying for species that depend on live coral reefs for food and shelter especially as studies have shown that protection of pristine habitats facilitate the persistence of adult populations in species that have spatially separated adult and juvenile habitats. Furthermore, coral reef loss and declining habitat conditions are particularly worrying for some corallivorous excavating parrotfishes that play major roles in reef dynamics and sedimentation (Comeros-Raynal et al. 2012).

Threat classification from the IUCN Red List.

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Last Update: June 28, 2026