Marine life  /  Butterflyfish  /  Eastern triangular butterflyfish
Reviewed 2026-09-06
Species entry

Eastern triangular butterflyfish

Chaetodon baronessa

Chevrons on grey, and a diet narrow enough to tie it to the corals it feeds on.

Size
To 16 cm
Depth
3–25 m
Habitat
Soft coral on reef slopes and rubble
Active
Daylight
Range
Indo-Pacific
Rarity
Lembeh Strait
2 stars of 5, usually seen in a week
SP-01
eastern triangular butterflyfish · full body · habitat
4:3 · min 2400px

To about 16 cm, grey with a series of fine dark chevrons pointing backwards across the flanks, two orange-brown bars across the head and a pointed snout. The very similar Chaetodon triangulum has a triangular black patch on the tail and replaces this species in the Indian Ocean.

It feeds almost exclusively on the polyps of Acropora and, in this region particularly, on soft corals of the genus Xenia, which restricts it to reefs carrying those. Pairs hold small feeding territories and defend them against other butterflyfishes. It is a small, quick fish that works continuously over a colony, so the photograph is generally taken at the colony rather than by following the fish. Recorded from about 3 to 30 m.

Where to find:

LocationRarity Best monthsDepthHabitat
Lembeh Strait Indonesia editorial estimate
2 stars of 5, usually seen in a week
Year-round
3–25 m
Soft coral on reef slopes and rubble
Bali Indonesia editorial estimate
2 stars of 5, usually seen in a week
Year-round
3–30 m
Soft coral on reef slopes
Anilao Philippines editorial estimate
2 stars of 5, usually seen in a week
Year-round
3–25 m
Soft coral on reef and rubble
Papua New Guinea Papua New Guinea editorial estimate
2 stars of 5, usually seen in a week
Year-round
3–30 m
Soft coral on reef slopes
Dauin & Dumaguete Philippines editorial estimate
3 stars of 5, a good week should turn one up
Year-round
3–25 m
Soft coral on rubble

Ratings are per location: 1 means found on most dives that look for it, 5 means a handful of records. Where enough dives have been logged the figure is calculated from them; otherwise it is an editorial estimate, and says so. We publish habitat and destination, not the dive site.

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