Stegastes rocasensis
Endemic damselfish spotted around Fernando de Noronha in warm 27C water, common on reef patches nearly year-round.
A small, stocky damselfish topping out around 6 cm, with a deep oval body typical of the genus. Colouring runs dusky brown to grey-brown with a faint pale edge on the tail, easy to overlook against rubble and rock. Look for it holding a fixed position over a patch of reef rather than schooling, a habit that gives away its territorial nature before you even clock the colour.
Divers typically find it parked over a small territory of rock or reef, defending that patch against other fish rather than roaming open water. It is unbothered by divers holding steady at a respectful distance, but like most damselfish it will dart at anything, fish or fin, that gets too close to its patch. Most sightings come from the shallower rocky reef areas rather than deep drop-offs.
As an endemic of the Fernando de Noronha and Rocas Atoll region, this damselfish's entire known range sits within a tiny stretch of Brazilian offshore islands, making it one of the more geographically restricted damselfish anywhere.
Sightings show no clear seasonal pattern, and with water sitting steadily around 27 to 27.6 C, it is present on the reef year-round. Plan around Fernando de Noronha's diving season generally rather than around this fish specifically.
Reef neighbours a diver could mistake it for. Use the identification notes above to tell them apart.
This one is effectively a Fernando de Noronha specialty, logged across dive sites there and nowhere else in the current data. If you are diving Brazil's oceanic islands, it is a reliable find on the reef patches and rocky slopes around Noronha rather than something to chase on the mainland coast.
Mapping where Rocas Gregory is logged…
It is most reliably seen around Fernando de Noronha, Brazil, where it turns up on rocky reef patches at numerous dive sites. Sightings in the current data are concentrated entirely in this region.
There is no strong seasonal pattern in sightings, and water temperature stays close to 27 C year-round, so it is a fairly consistent find whenever you are diving Fernando de Noronha.
Look for a small, oval-bodied damselfish around 6 cm long, brownish-grey overall, holding a fixed position over a patch of rock or reef instead of schooling. Its territorial hovering is often the first clue, before you even pin down the colour.
They stay small, typically around 6 cm long, in keeping with most damselfish in the Stegastes genus.
No. It poses no threat to divers, though like other damselfish it may dart towards a fin or hand that strays into its territory.
It is endemic to a very small corner of the ocean, the Fernando de Noronha and Rocas Atoll region off Brazil, and is not known to occur anywhere else, unusually restricted for a reef damselfish.
Site and sighting data is aggregated from diver logs, iNaturalist and GBIF. For taxonomy and conservation status:
Yellowtail Clownfish
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