HomeMarine aquarium fishAngelfish & butterflyfishTriangle butterflyfish Triangle butterflyfish (Chaetodon triangulum) Scientific name: Chaetodon triangulum Cuvier, 1831 The Triangle butterflyfish (Chaetodon triangulum) is a marine fish of the family Chaetodontidae. Native range: Indian Ocean, Madagascar to the Andaman Sea and western sector of the Indonesian Archipelago. BiologyDeep-bodied and black triangle in caudal fin.Source: FishBase, licensed CC BY-NC 4.0. Species factsScientific nameChaetodon triangulumFamilyChaetodontidae (Butterflyfishes)OrderPerciformes (Perch-like fish)ClassActinopterygii (Ray-finned fishes)Maximum length16.0Depth range25 m (82 ft)EnvironmentMarine; reef-associated; depth range ? - 25 mClimateTropicalDistributionIndian Ocean: Madagascar to the Andaman Sea and western sector of the Indonesian Archipelago.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 nematopteraRedtail butterflyfishChaetodon collareBluestriped butterflyfishChaetodon frembliiPebbled butterflyfishChaetodon multicinctusBanded angelfishApolemichthys arcuatusRusset angelfishCentropyge potteriSee 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