Pycnochromis atripes
A small reef damselfish most reliably found around Milne Bay, Papua New Guinea, in warm 26-29C water year-round.
A compact damselfish that tops out around 6cm, easy to overlook among bigger reef fish. Body is dark, generally a smoky grey-brown to blackish shade, with fins that read slightly darker at the edges, giving it its name. Shape is the classic chromis silhouette: oval, laterally flattened, with a forked tail, and it holds station just off the reef rather than hugging the substrate.
Typically seen hovering in loose groups just above the reef, picking plankton out of the water column rather than feeding on the bottom. It stays close to coral or rubble it can dart into if threatened, and shows little concern for divers who keep a normal distance. Look for it over reef slopes and patches during the day, mixed in with other small damselfish rather than sitting alone.
Like most chromis, it feeds mainly on drifting plankton, which is why you'll usually spot it suspended in the water above the reef rather than picking at coral or rock.
No clear seasonal pattern shows up in the data, and with a comfortable range of 25.6 to 28.8C it is present on these reefs year-round. Plan around the diving season for Milne Bay or Raja Ampat rather than around this fish specifically.
Reef neighbours a diver could mistake it for. Use the identification notes above to tell them apart.
Most reliably logged around Milne Bay in Papua New Guinea, which accounts for the bulk of recorded sightings, with additional records from Dili in Timor-Leste and Raja Ampat in Indonesia. Divers rate it common at most Milne Bay sites, so it is a reasonable bet on a Papua New Guinea reef trip rather than a needle-in-a-haystack find.
Mapping where Darkfin Chromis is logged…
Milne Bay in Papua New Guinea is the strongest area for sightings, logged as common at most sites there. It has also been recorded near Dili in Timor-Leste and in Raja Ampat, Indonesia.
There is no distinct season in the sighting data, and the water temperatures it's found in, roughly 25.6 to 28.8C, hold steady on tropical reefs year-round, so any time you're diving Milne Bay or Raja Ampat works.
Look for a small, dark grey-brown damselfish around 6cm long, oval-bodied with a forked tail, hovering in loose groups above the reef rather than sitting on it. The fin edges typically appear a shade darker than the body.
They stay small, reaching around 6cm, so they're easy to miss among larger reef fish unless you're looking closely at the water column just above coral.
No. They pose no threat to divers and will simply dart back into reef cover if you get too close.
Site and sighting data is aggregated from diver logs, iNaturalist and GBIF. For taxonomy and conservation status:
Yellowtail Clownfish
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