Lieutenant Tang

Overview

The Lieutenant Tang (Acanthurus tennentii) — also called the Tennenti Tang or Doubleband Surgeonfish — is a sophisticated, understated surgeonfish that experienced reefers tend to fall for. It skips the loud colours of a Powder Blue or Clown Tang in favour of a smooth matte tan-to-olive body with a dark outline, blue highlights along the tail, and its namesake pair of black bars behind the eye that look just like a lieutenant's rank insignia (some see vampire fangs — hence its other nickname).

As it matures it develops an elegant lyre-shaped tail with trailing tips, and juveniles often carry a yellow tinge that fades with age. It's a hardworking algae grazer and, importantly, one of the more even-tempered large Acanthurus — relatively peaceful for the genus, if still no pushover.

We rate it intermediate mainly on account of its adult size, its need for serious swimming room and strong flow, and the usual tang susceptibility to parasites. Give it the space and water quality it wants and it's a graceful, long-lived centrepiece that earns its keep keeping your rockwork clean.

Compatibility

For an Acanthurus, the Lieutenant Tang is comparatively easygoing — it's peaceful toward dissimilar tankmates and generally isn't a troublemaker in a community. The exception is its own kind: like most tangs it can be territorial toward other surgeonfish, especially those of the same genus or a similar body shape and colour. As a rule, keep one per tank.

It mixes well with wrasses, anthias, larger angels, and tangs from other genera such as Zebrasoma or Naso. If you do want to run multiple tangs, add them all at once (or very close together) in a large system so no single fish claims the territory first. Take care with the sharp caudal scalpel when netting or working in the tank, and give it open swimming lanes to keep any squabbling to a minimum.

Health & quarantine

Like all tangs, the Lieutenant lacks a heavy body-slime coat and is prone to marine ich and other parasites, particularly through the stress of collection and acclimation. A proper quarantine period and a slow, unhurried acclimation are strongly recommended and greatly improve long-term success. This is a seaward-reef and surge-zone fish, so it also demands strong, well-oxygenated flow and pristine, stable water — good filtration, a decent skimmer and plenty of movement all help. Cleaner shrimp and cleaner wrasses make useful allies, and a varied, algae-rich diet supports its immune system while guarding against head-and-lateral-line erosion (HLLE).