Pycnochromis pacifica
A small blue-grey damselfish logged most often around Hawaii, holding steady in 24.6-28.8C water year-round.
Small and slender for a damselfish at around 6 cm, with a slim body that's grey to pale blue and a faintly forked tail. Look for the plain, unpatterned body and the way it hovers in loose groups just off the reef structure rather than sitting tight against it. There's no strong facial marking or bold stripe to key on, so size, shape, and habit do more of the work than colour.
Divers typically find it hovering in small, loose groups over reef structure rather than schooling tightly or hiding in the substrate. It's an unobtrusive fish that goes about picking at plankton in the water column and doesn't react much to divers passing by, which is part of why it gets logged as uncommon rather than something people specifically hunt for.
Like most damselfish, it feeds mainly by plucking plankton straight out of the water rather than grazing algae off the reef, so you'll usually see it stationed a bit above the bottom rather than nose-down on coral.
No clear seasonal pattern shows up in the sightings, and the 24.6-28.8C range it's found in holds year-round on these reefs, so any month works.
Reef neighbours a diver could mistake it for. Use the identification notes above to tell them apart.
Most consistently logged in Hawaii, where it turns up across a wide spread of sites, with a smaller but reliable presence in Guam, including Tumon Bay, the North Coast, and Apra Harbor. Hawaii is by far the stronger bet if you're planning a trip specifically to find one.
Mapping where Agile Chromis is logged…
Hawaii is the strongest bet, with sightings spread across many sites there. Guam also has a smaller but reliable population, notably around Tumon Bay and the North Coast.
There's no detected season for this one. Water in its observed range stays between about 24.6 and 28.8C year-round, and sightings don't cluster in particular months, so it's a year-round fish on the reefs where it's found.
Look for a small, slender grey-to-blue damselfish around 6 cm long, hovering in loose groups just off the reef rather than schooling densely or hugging the bottom. It lacks strong stripes or facial markings, so its plain colouring and mid-water hovering habit are the main clues.
They stay small, topping out around 6 cm, which is typical for damselfish in this group.
No. They're a small, harmless damselfish that pays little attention to divers and poses no risk.
Site and sighting data is aggregated from diver logs, iNaturalist and GBIF. For taxonomy and conservation status:
Yellowtail Clownfish
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