Pempheris vanicolensis
Uncommon schooling fish found in caves and overhangs across Sabah, Malaysia, in warm 25-29C reef water year-round.
A slim, deep-bodied little fish around 14 cm, with a silvery to coppery-brown flank and a noticeably large, dark eye that helps it see in the dim spots it favours. The body is compressed and almost see-through toward the tail, and it tends to hang nose-down or at odd angles in small clusters rather than swimming level like most reef fish. Look for it tucked into cave mouths, under ledges, or beneath jetties rather than out in open water.
Expect to find small, loose groups tucked into shaded recesses, cave entrances and under jetties or overhangs during the day, often hovering at an angle rather than swimming flat. It reads as shy and sedentary in daylight, holding position near cover rather than roaming the reef face, which fits its habit of feeding more actively after dark. Divers rarely get a strong reaction from it beyond a slight retreat deeper into the shadow when a torch or camera gets close.
Sweepers in this family are largely nocturnal feeders, spending daylight hours packed into caves and overhangs before dispersing to feed on plankton after dark, which is why daytime encounters are usually of resting, tightly clustered groups rather than active fish.
No clear seasonal pattern shows up in the sightings, and with water temperatures logged between 25.3 and 29.3C, this is a warm-water reef fish present year-round. Plan your dive around the site rather than the calendar.
Reef neighbours a diver could mistake it for. Use the identification notes above to tell them apart.
Sightings concentrate heavily in Sabah, Malaysia, where divers log it far more than anywhere else in the current data. A smaller number of sightings come from Efate, Vanuatu, so while it turns up across the Indo-Pacific, Sabah is the region to target if you want a real shot at finding one.
Mapping where Vanikoro Sweeper is logged…
Sabah, Malaysia is by far the most reliable region for this species in the current sighting data, with a much smaller number of records from Efate, Vanuatu. Look in caves, under ledges and beneath jetties rather than open reef.
There is no detected seasonal pattern, and the species is logged in water between 25.3 and 29.3C, consistent with year-round presence on tropical reefs. Any time of year should work at the right dive sites.
Look for a small, slim, silvery-brown fish around 14 cm with a large dark eye, often hovering at an angle in small groups inside caves or under overhangs rather than swimming in open water.
They reach around 14 cm, making them a modest-sized schooling fish that is easy to overlook unless you check dark crevices and overhangs closely.
No, they pose no threat to divers and are generally shy, retreating deeper into their cave or ledge when approached rather than reacting defensively.
Site and sighting data is aggregated from diver logs, iNaturalist and GBIF. For taxonomy and conservation status:
Pempheris schomburgkii
Anchovy
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