Description

• Scientific Name: Acanthurus tennentii
• Common Names: Doubleband Surgeonfish, Lieutenant Surgeonfish, Tennent’s Surgeonfish
• Maximum Length: 12 inches (31 cm)
• Minimum Aquarium Size: 180 gallons (681 liters) for a single fish. Their active grazing and territorial behavior require plenty of swimming space and rockwork.
• Foods and Feeding Habits: Herbivorous, grazing on benthic algae in the wild. In aquariums, offer algae-based flakes or pellets with spirulina, nori sheets, and occasional vegetable matter like zucchini or lettuce. Feed 2-3 times daily. A tank with natural algae growth supports their diet and health.
• Reef Safety: Reef-safe with caution; they generally don’t harm corals but may nip at sessile invertebrates if underfed. Ensure ample algae to keep them content.
• Temperament: Semi-aggressive, territorial toward conspecifics or similar surgeonfish. Best kept singly; provide hiding spots and introduce as one of the last additions to reduce conflicts.
• Description: The Lieutenant Surgeonfish is a hardy grazer appreciated for algae control in marine tanks. Its body is brownish with two prominent dark vertical bands forming a horseshoe shape on the shoulder, yellow-edged dorsal and anal fins, and a white-ringed tail spine. Native to the Indian Ocean, from East Africa to Indonesia, they inhabit lagoons and seaward reefs at depths of 1-40 meters. Sensitive to stress, they thrive in mature tanks with excellent water quality, rewarding keepers with their active foraging behavior.

Fun Facts:

• Named after Sir James Emerson Tennent, a British colonial administrator who collected specimens in Sri Lanka during the 19th century.
• Their distinctive double bands resemble a horseshoe, earning them the French name “Poisson-chirurgien fer à cheval.”
• Like other surgeonfish, they can rapidly change color to darker shades when stressed, aiding in camouflage among reefs.