Lieutenant Surgeonfish Care Guide
Acanthurus tennentii · Saltwater Tang
What Lieutenant Surgeonfish look like
The Lieutenant Surgeonfish, scientifically known as Acanthurus tennentii, exhibits a laterally compressed body that can reach a maximum adult size of approximately 12 inches (30 cm). This species is characterized by its striking coloration, featuring a vibrant blue to bluish-gray body adorned with a prominent yellow stripe that runs diagonally from the eye to the base of the tail. Sexual dimorphism is minimal, though males may display slightly more vibrant coloration during breeding periods. The fish possesses a unique pair of sharp, retractable spines on either side of the tail, which serve as defensive adaptations against predators. Additionally, the dorsal fin is elongated and pointed, contributing to its streamlined appearance, while the anal fin is similarly shaped, providing stability during swimming.
Behavior & temperament
Lieutenant Surgeonfish are typically found in small to medium-sized schools, exhibiting a social hierarchy where dominant individuals establish territories within the group. They primarily inhabit the reef's upper levels, often seen grazing on algae and detritus. During breeding, males engage in courtship displays that involve rapid swimming and color changes to attract females. Their temperament is generally peaceful, although they can exhibit territorial aggression towards conspecifics or other tangs, particularly in confined spaces.
Diet & feeding
In the wild, Lieutenant Surgeonfish primarily feed on algae, making them herbivorous grazers. In captivity, they require a diet rich in marine algae, high-quality herbivore pellets, and occasional vegetable matter to maintain optimal health.
Behind the name
The genus name 'Acanthurus' is derived from the Greek words 'akanthos,' meaning thorn, and 'oura,' meaning tail, referencing the sharp spines on the tail. The species name 'tennentii' honors the naturalist William Tennent.
Plan your tank
Check the numbers before you buy: tank volume, salinity, salt mix, water changes, and your ongoing care routine.
Keeping Lieutenant Surgeonfish?
AquaLens identifies your fish and plants from a photo, tracks water chemistry, and flags health issues early — free on iOS and Android.
