Abudefduf sordidus
Chunky reef damselfish with dark bars, common in shallow water from Hawaii to Phuket year-round in 24-29C reefs.
Stocky, oval-bodied damselfish around 16 cm with five or six dark vertical bars over a pale grey-white body, plus the namesake black spot near the base of the tail. The bars are broader and duller than on close relatives, giving it a slightly washed-out, olive-grey look rather than crisp black and white. It stays close to shallow rock and reef structure, rarely straying more than a metre or two off the bottom.
Look for it hovering or darting around rock crevices and shallow reef flats in the top few metres of water, often in loose groups rather than tight schools. It holds its ground fairly well around divers and snorkelers rather than bolting, though it will dip back into a crevice if approached too fast. Most sightings come from shallow, sheltered spots close to shore rather than deep reef walls.
Like other Abudefduf damselfish, breeding adults guard a patch of reef where eggs are laid on rock or dead coral, and will dart at anything, including a diver's hand, that gets too close to the nest.
No clear seasonal pattern shows up in the data, and with a comfortable range of 24.7 to 29.3C it is present on shallow tropical reefs all year round.
Reef neighbours a diver could mistake it for. Use the identification notes above to tell them apart.
Most reliably logged in Hawaii, where it turns up on shallow reef and rocky shoreline sites across the islands, and it is also a strong presence on Malaysia's east coast peninsula. French Polynesia's Society Islands and the Seychelles' Inner Islands are other consistent spots, with additional sightings around Phuket, Koh Chang, Koh Lipe and Koh Tao in Thailand.
Mapping where Blackspot Sergeant is logged…
Hawaii is the most reliable place, with strong numbers also logged on Malaysia's east coast, in French Polynesia's Society Islands, and around the Seychelles' Inner Islands. Thailand's Phuket, Koh Chang, Koh Lipe and Koh Tao also produce regular sightings.
There is no strong seasonal pattern in sightings, and it tolerates a wide 24.7 to 29.3C range, so it is a year-round fish on the reefs where it occurs.
Look for a stocky, grey-white damselfish around 16 cm long with five or six dark, slightly faded vertical bars and a distinct black spot near the tail base. It sticks close to shallow rock and reef structure rather than open water.
They typically reach around 16 cm in length, a compact, deep-bodied fish that stays easy to overlook among the rock and reef clutter it favours.
No, they pose no danger to divers. Nesting adults may dart aggressively at anything near their egg patch, but this is only a startle response, not a real threat.
Site and sighting data is aggregated from diver logs, iNaturalist and GBIF. For taxonomy and conservation status:
Yellowtail Clownfish
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