Chaetodon xanthurus
Spot this pearly, orange-scrawled butterflyfish on reefs in Sulawesi, Luzon and the Visayas, uncommon but year-round in warm 26-30C water.
A small, compact butterflyfish around 9cm, with a body covered in fine orange-yellow scribbled lines over a pale pearly background, giving it a scaled, almost engraved look. A broad black band runs through the eye, and the rear body and tail carry a strong orange-yellow wash that fades toward the caudal fin. The overall pattern reads as busier and more mottled than most Chaetodon species, which is the quickest tell at a glance.
Usually seen picking around coral heads and rubble patches on the reef slope, singly or in loose pairs, browsing on small invertebrates and algae rather than schooling. It tends to keep a cautious distance from divers and will duck into coral cover if approached too fast, so a slow, low approach gives the best look. Most sightings come from mid-depth reef, well within the range most recreational divers work.
Like other Chaetodon butterflyfish, it likely pairs up on the reef and defends a small feeding territory rather than roaming widely, which is why the same individual can often be found in the same coral patch dive after dive.
No clear seasonal pattern shows up in the data, and with a comfortable range of roughly 26 to 30C across its range, it turns up on reefs year-round rather than in a particular window.
Reef neighbours a diver could mistake it for. Use the identification notes above to tell them apart.
Most reliably logged across the Philippines, especially Luzon, the Visayas, Palawan and Mindanao, and in Indonesia, with Sulawesi standing out as a strong region. Thailand, Malaysia (notably Sabah) and Vietnam also produce regular sightings, with fewer records from Japan, Cambodia and Brunei.
Mapping where Pearlscale Butterflyfish is logged…
Best chances are in the Philippines, particularly Luzon, the Visayas, Palawan and Mindanao, and in Indonesia around Sulawesi. Thailand, Sabah in Malaysia and Vietnam also have regular records.
There is no strong seasonal signal in the sighting data, and it lives in warm 26 to 30C reef water year-round, so any month on a tropical reef trip is fair game.
Look for a small, roughly 9cm butterflyfish with pearly scales scrawled in orange-yellow lines, a black eye band, and an orange wash toward the tail. The busy, scribbled pattern sets it apart from plainer Chaetodon species.
They stay small, reaching around 9cm, which is typical for reef-associated Chaetodon butterflyfish and part of why they can be easy to miss on a busy reef.
No, they are harmless to divers, spending their time picking at coral and rubble and keeping their distance rather than showing any defensive or aggressive behaviour.
Site and sighting data is aggregated from diver logs, iNaturalist and GBIF. For taxonomy and conservation status:
