HomeMarine aquarium fishAngelfish & butterflyfishEastern triangular butterflyfish Eastern triangular butterflyfish (Chaetodon baronessa) Scientific name: Chaetodon baronessa Cuvier, 1829 The Eastern triangular butterflyfish (Chaetodon baronessa) is a marine fish of the family Chaetodontidae. BiologyDorsal spines (total): 11 - 12; Dorsal soft rays (total): 23-26; Anal spines: 3; Anal soft rays: 20 - 22. The sides are with a pattern of alternating cream and grey-brown to purplish chevron-shaped narrow bars. Three dark bars on the head, including one running across the eye.Source: FishBase, licensed CC BY-NC 4.0. Species factsScientific nameChaetodon baronessaFamilyChaetodontidae (Butterflyfishes)OrderPerciformes (Perch-like fish)ClassActinopterygii (Ray-finned fishes)Maximum length16.0Depth range5–20 m (16–66 ft)EnvironmentMarine; reef-associated; non-migratory; depth range 5 - 20 mClimateTropicalDistributionWestern Pacific: Cocos-Keeling Islands in the eastern Indian Ocean and Indonesia to Fiji and Tonga, north to southern Japan, south to New Caledonia and New South Wales, Australia. Replaced by Chaetodon triangulum in the Indian Ocean.Conservation status (IUCN)Least Concern (LC)Threat to humansHarmlessUsesAquarium: commercialResilienceHigh, minimum population doubling time less than 15 months (Preliminary K or Fecundity.) More angelfish & butterflyfishPajama cardinalfishSphaeramia nematopteraThreadfin butterflyfishChaetodon aurigaBluelashed butterflyfishChaetodon bennettiBurgess' butterflyfishChaetodon burgessiSpeckled butterflyfishChaetodon citrinellusSaddle butterflyfishChaetodon ephippiumSee all angelfish & butterflyfish SourcesTaxonomy, distribution and biology data: FishBase (Froese, R. and D. Pauly, eds.), licensed CC BY-NC 4.0.Last updated 27 September 2026