Chromis weberi
A small blue-grey damselfish spotted off Dili, Timor-Leste and Bali reefs in warm 26-29C water, year-round but always in modest numbers.
A slim, torpedo-shaped damselfish around 9 cm long, pale blue-grey overall with a faint darker shading along the back and a distinctly forked tail. It lacks the bold bars, spots or eye-catching colour patches that mark many reef damselfish, which is itself a useful clue: if you're looking at a plain, unremarkable blue-grey fish hovering just off the reef, this is a strong candidate. Look for the slender profile and the forked tail shape rather than any single flashy mark.
Typically seen hovering alone or in loose, small groups just above the reef structure, picking at drifting plankton rather than feeding directly off the substrate. It keeps a fairly relaxed distance from divers, neither bolting for cover nor approaching, and tends to stay in the same patch of reef across a dive. Logged across a wide depth range from the shallows down to 40 metres, so it's not fussy about reef depth as long as there's structure to shelter near.
It's logged as uncommon at every site where divers have recorded it, so unlike many of its more sociable damselfish relatives it rarely forms the dense, eye-catching clouds you get with some Chromis species, making a confident sighting feel more like a small find than a given.
No clear seasonal pattern shows up in the sightings, and with a comfortable temperature range of 25.8 to 29C it has no reason to disappear seasonally on the tropical reefs where it's found. Plan around good conditions at your chosen site rather than a particular month.
Reef neighbours a diver could mistake it for. Use the identification notes above to tell them apart.
Most reliably logged around Dili in Timor-Leste, with further sightings in Bali, Indonesia and the South Sinai coast of Egypt. Smaller pockets turn up in the Visayas in the Philippines, Lomaiviti in Fiji, and Xiaoliuqiu in Taiwan, so it's a fish spread thinly across a wide swathe of the Indo-Pacific rather than concentrated in one hotspot.
Mapping where Weber's Chromis is logged…
It turns up most often around Dili in Timor-Leste, with further sightings in Bali, Indonesia and along the South Sinai coast of Egypt. Smaller numbers have also been logged in the Visayas in the Philippines, Fiji's Lomaiviti region and Xiaoliuqiu in Taiwan.
There's no detected seasonal pattern, and it sits comfortably in 25.8 to 29C water year-round, so any time you're diving warm tropical reefs in its range is fair game.
Look for a small, slender blue-grey fish around 9 cm long with a forked tail and no strong stripes or spots. Its plainness compared to showier damselfish is actually the giveaway when paired with its typical hovering posture just off the reef.
They max out at around 9 cm, putting them firmly in the small-damselfish category you'd expect to see hovering in loose groups rather than solo giants.
No. It poses no threat to divers and simply goes about its business hovering near the reef, ignoring passing divers.
Site and sighting data is aggregated from diver logs, iNaturalist and GBIF. For taxonomy and conservation status:
Yellowtail Clownfish
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