Chaetodon ocellicaudus
A white-and-black reef fish with a bold tail spot, most reliably found on reefs across Sulawesi, Luzon and the Visayas year-round.
A small, disc-shaped butterflyfish around 10 cm, with a white body crossed by black bands through the eye and rear flank. The giveaway is the bold black spot sitting on the tail base (peduncle), which is what separates it from most other white-and-black chaetodontids on the reef. It swims with the typical butterflyfish gait: slow, flattened, and always angled toward cover.
Usually spotted picking around coral heads and rubble patches alone or in loose pairs, nosing into crevices for small invertebrate prey rather than schooling in open water. It tends to hold its ground near reef structure and eases off into cover rather than bolting when divers approach, which is why most logs describe it as uncommon rather than absent. Sightings span a wide depth range, from shallow reef flats down past 30 metres, so it is worth checking both the shallows and the deeper reef slope.
It sits in the same genus as many classic Indo-Pacific butterflyfish but its range is noticeably tighter, concentrated on the coral triangle reefs of the Philippines and Indonesia rather than spread ocean-wide like its more familiar relatives.
No clear season shows up in the sighting data, and with a comfortable range of roughly 27.5 to 29.5 C it stays on tropical reefs year-round, so any month at these sites is fair game.
Reef neighbours a diver could mistake it for. Use the identification notes above to tell them apart.
Most reliably logged across Indonesia and the Philippines, with Sulawesi, Luzon, the Visayas, Palawan and Mindanao standing out as the strongest regions. It also turns up with good regularity in Sabah (Malaysia) and around Pattaya in Thailand, with smaller but real populations reported from Vietnam, Cambodia, Papua New Guinea and parts of Australia.
Mapping where Spot-tail Butterflyfish is logged…
Best chances are on reefs in Sulawesi and Raja Ampat in Indonesia, and Luzon, the Visayas, Palawan and Mindanao in the Philippines. Sabah in Malaysia and Pattaya in Thailand also produce regular sightings.
There is no strong seasonal pattern in the data, and its warm-water niche of about 27.5 to 29.5 C is available year-round across its Southeast Asian range, so any month works.
Look for a small white butterflyfish with black bands across the head and body, plus a distinctive black spot on the tail base. That tail spot is the fastest way to separate it from similar-looking white-and-black chaetodontids.
They stay small, topping out around 10 cm, typical for reef-associated butterflyfish that feed on small invertebrates rather than needing bulk.
No. They are harmless reef fish with no venom or aggressive behaviour toward divers, and will simply move off toward cover if you get close.
Site and sighting data is aggregated from diver logs, iNaturalist and GBIF. For taxonomy and conservation status:
