News / Species Spotlight / Lieutenant Tang (Acanthurus tennentii) (06/11/18)

Lieutenant Tang (Acanthurus tennentii)

Species Spotlight - Lieutenant Tang (Acanthurus tennentii)
The Lieutenant Tang is named for its distinctive pair of black stripes, which recalls the pair of stars or stripes worn by military officers of that rank. The scientific name alludes to the 19th century British politician and naturalist James Emerson Tennent who wrote extensively on the natural history of Sri Lanka (then Ceylon), where this fish was originally described from.

Acanthurus tennentii is a widespread species in the Indian Ocean, absent only from the Red Sea. It is encountered in shallow inshore reefs, often where the substrate is heavily laden with silt. There is relatively little algae which grows in these habitats, so, instead, this fish feeds upon the nutritious upper layer of organic matter and microorganisms which abounds on the bottom. It is often seen singly or in pairs, but also in small groups.

In the Pacific Ocean, it is replaced by the similar Orange-shoulder Tang (A. olivaceus), adults of which have a unique bicolored appearance and a longer marking behind the head. Juveniles of these two sister species are markedly different, with A. olivaceus being bright yellow (similar to a Lemonpeel Angelfish) while A. tennentii is mostly grey. Where the two overlap (e.g. Christmas Island, Cocos Keeling Islands, Bali), hybrids are occasionally encountered, which look more or less like a Lieutenant Tang possessing the ghostly remnant of an orange-shoulder.

Both of these fishes are an excellent choice for larger aquariums, typically as solitary individuals. Fully grown specimens reach around one foot in length, and, at this size, can be pugnacious towards tankmates, especially other tangs or angelfishes.