Chaetodon sedentarius
A small, silvery butterflyfish with a dark cheek bar, uncommonly logged on reefs off Florida and Colombia's Caribbean coast year-round.
A small, disc-shaped fish around 10 cm, pale silvery-grey overall with fine dark scale lines giving it a subtly barred look. The giveaway is a dark vertical bar through the eye and a dark smudge near the base of the tail rather than a bold body pattern. It lacks the strong yellow wash or black-and-white banding seen on many of its relatives, which makes it look almost understated by comparison.
Usually seen alone or in loose pairs picking over reef structure and rubble patches, moving steadily rather than darting, and generally unbothered by a diver holding a respectful distance. It tends to stick close to cover such as ledges and coral heads, making brief forays out to feed before slipping back toward shelter.
Like other butterflyfish, it has a long snout suited to picking small invertebrates and other food items out of tight crevices that bigger-mouthed reef fish cannot reach.
Sightings show no clear seasonal pattern, and the species sits comfortably in water from about 22.7 to 28 C, so it is a year-round resident on the reefs where it occurs rather than a seasonal visitor.
Reef neighbours a diver could mistake it for. Use the identification notes above to tell them apart.
Most reliably logged on reefs off Florida in the United States and along the Caribbean coast of Colombia, with additional sightings around Rio de Janeiro in Brazil, Saint-Pierre in Martinique, and Tobago in Trinidad and Tobago. At most of these sites it turns up as an uncommon rather than everyday find, so patient reef scanning pays off.
Mapping where Reef Butterflyfish is logged…
Florida in the United States and Colombia's Caribbean coast are the most consistent spots, with smaller but real chances off Rio de Janeiro in Brazil, Saint-Pierre in Martinique, and Tobago in Trinidad and Tobago.
There's no strong season in the data. It tolerates a wide temperature range of roughly 22.7 to 28 C, so it is present on its home reefs throughout the year.
Look for a small silvery-grey fish about 10 cm long with a dark bar through the eye and a dark patch near the tail base, rather than bold yellow or black banding.
They stay small, typically around 10 cm, making them one of the more modestly sized members of the butterflyfish family.
No. They are harmless, small reef grazers with no sting or bite risk to divers.
Site and sighting data is aggregated from diver logs, iNaturalist and GBIF. For taxonomy and conservation status:
Melon Butterflyfish
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