Stegastes fuscus
A reef regular off Rio de Janeiro and Santa Catarina, spotted in waters from 23.6 to 28.1C on Brazil's rocky reefs.
A small, deep-bodied fish around 9 cm, coloured dark brown to sooty grey with a faintly speckled look up close. The body is oval and compact, with a blunt head and a single continuous dorsal fin typical of damselfish. There's no bold pattern to key on here, it's more about the stocky shape, dark colouring, and the way it holds territory over a patch of reef rather than schooling freely.
Look for it holding a patch of rock or reef and defending it, damselfish are famous for chasing off anything that strays too close, divers included on occasion. It tends to stay put rather than range widely, hovering just above its patch and darting back to cover when startled. Most sightings are logged as uncommon rather than common at a given site, so it's a fish you notice one or two of per dive rather than in numbers.
Like many damselfish, it likely tends an algae patch on its home rock, weeding out unwanted growth and guarding the spot fiercely against intruders, a behaviour that makes it easy to watch if you just stay still nearby.
Sightings don't show a clear seasonal pattern, and with a comfortable range of 23.6 to 28.1C, it's likely present on these reefs year-round rather than tied to a particular month.
Reef neighbours a diver could mistake it for. Use the identification notes above to tell them apart.
This one is a Brazil specialty, most reliably logged along Rio de Janeiro and Santa Catarina, with a smaller presence in Pernambuco further north. If you're diving the rocky reefs of southeastern Brazil, it's a common enough find that you don't need to go looking hard.
Mapping where Dusky Damselfish is logged…
It's most consistently spotted in southeastern Brazil, particularly around Rio de Janeiro and Santa Catarina, with a smaller number of sightings in Pernambuco.
There's no strong seasonal pattern in the sighting data, and it tolerates a wide temperature range from about 23.6 to 28.1C, so it's a year-round find on Brazilian reefs rather than a seasonal one.
Look for a small, deep-bodied fish around 9 cm long, dark brown to grey in colour with a faintly speckled texture. It's usually seen alone or in low numbers, holding position over a specific patch of reef rather than schooling.
They're small, typically reaching around 9 cm, which is standard for damselfish in the Pomacentridae family.
No, they pose no danger to divers. They can be territorial and may dart towards a diver who lingers too close to their patch, but this is only a minor nuisance, not a real threat.
Site and sighting data is aggregated from diver logs, iNaturalist and GBIF. For taxonomy and conservation status:
Yellowtail Clownfish
3,523 sites
