Epaulette Tang - Acanthurus nigricauda

Medium (3.1-4")

$259.99

Reef Safe Tang

$259.99

Size Small (1.75-2.25") SM (2.26-3") Medium (3.1-4") ML (4.1-5") Large (5.1-6") XL (6.1-7") XX (7.1-8") SHOW (8.1-10") Jumbo (10.1-11")

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Goes well with:

Diet

algae/nori spirulina mysis brine shrimp

Min Tank Size 125 gallons

Temperament Semi-aggressive

Reef Safe Yes

Care & Diet Feeding, nutrition, and best practices.

Diet Type: Omnivore

Diet and Feeding: Epaulette Tang are primarily herbivorous algae grazers in nature, spending much of the day browsing filamentous algae, turf algae, and other marine plant matter with incidental detritus and microfauna. In captivity, it is beneficial to make the bulk of the diet high-quality marine algae and herbivore fare such as nori (red and green seaweed), dried seaweed sheets, spirulina-based flakes, herbivore pellets, and algae wafers. To ensure balanced nutrition, supplement regularly with small portions of mysis shrimp, enriched brine shrimp, finely chopped clam or krill, and occasional frozen herbivore blends, while keeping these richer foods as treats rather than staples. Offer seaweed on a clip or feeding grid and rotate feeding locations to encourage natural foraging and grazing behavior. Feed small amounts 2–3 times daily, removing uneaten food promptly, and avoid overfeeding to maintain water quality and prevent digestive issues.

algae/nori spirulina mysis brine shrimp

Behavior Temperament, activity level, and interactions.

Temperament: Semi-aggressive

Epaulette Tang is an active, constant swimmer that spends most of the day cruising open water and grazing, so it requires ample length for uninterrupted swimming along with areas of rockwork for refuge and foraging. Temperament is generally semi-aggressive and highly territorial, especially toward conspecifics and other similarly shaped tangs, so it is best kept singly unless in a very large system. A minimum tank size of 120 gallons is recommended, with plenty of open space, strong water movement, and visual barriers created by rockwork to break up sightlines and reduce territorial disputes. In mixed communities, it can coexist with robust, reef-safe species and is usually reef-safe itself, though it may become domineering toward passive tank mates or other surgeonfish. Dietary habits are primarily herbivorous to omnivorous, with a strong preference for algae and other plant matter, supplemented by marine-based prepared foods and occasional meaty fare. Frequent grazing is important for both health and behavior, and a varied diet helps prevent stress and aggression.

Tank & Aquascape Tank requirements and aquascaping tips.

Min Tank Size: 125 gallons
Max Size: 10 inches
Care Level: Moderate
Origin: Indo-Pacific

Compatibility Tank mates, aggression, and introduction order.

Temperament: Semi-aggressive
Reef Safe: Yes

Reef & Health Reef safety, common issues, and prevention.

Reef Safe: Yes
Care Level: Moderate

FAQs Answers to the most common questions.

How big of an aquarium does an Epaulette Tang really need, and is a 4-foot tank enough long-term?

For a healthy adult Epaulette Tang, a 6-foot tank is the realistic minimum, with 180 gallons or larger being a better long-term home. A 4-foot tank may work only for a very small juvenile for a short time, but these tangs are active swimmers and need length more than height. In undersized tanks they often become stressed, which shows up as reduced feeding, pacing, and aggression.

Is an Epaulette Tang one of the tangs that will actually eat algae all day, or does it need a very specific diet?

It is not an algae-only fish. An Epaulette Tang should be fed a varied herbivore diet with marine algae as the core: nori, spirulina-based foods, high-quality pellets, and frozen foods like mysis or brine shrimp in moderation. Like many tangs, it grazes constantly, so small feedings or clipped seaweed offered daily are ideal. Good nutrition is important because poor diet often leads to faded coloration and a weakened immune system.

How aggressive is an Epaulette Tang compared with other tangs, and what tankmates usually cause problems?

It can be territorial, especially toward other tangs and similarly shaped fish. It usually does best when added to a spacious tank before more aggressive tankmates establish territory. Problems are most common with other Acanthurus tangs, similarly colored fish, or any fish competing for the same grazing space. Peaceful community fish are usually fine, but cramped tanks make even a normally manageable Epaulette Tang become aggressive.

What are the biggest warning signs that an Epaulette Tang is stressed or declining in health?

The biggest red flags are loss of appetite, heavy breathing, lingering in corners, rapid color fading, frayed fins, and visible white spots or dusty patches. Tangs also commonly show early stress by rubbing on rocks or flashing against objects. Because they are sensitive to poor water quality and transport stress, any sign of suppressed feeding should be treated seriously. Stable salinity, strong oxygenation, and pristine water are essential.

Does an Epaulette Tang need extra current and oxygen, or can it do fine in a normal reef tank flow?

It does best with strong, varied flow and excellent oxygenation. This species comes from high-energy reef environments and is built to handle moving water, so a low-flow tank often leaves it listless. The best setup is brisk circulation with some calmer areas for resting, plus strong surface agitation to keep oxygen levels high. In warm tanks, low oxygen is one of the fastest ways to stress a tang.

Almost WYSIWYG – you will receive a similar fish in shape and color to the species shown.

Epaulette Tang – Acanthurus nigricauda

The Epaulette Tang, also known as the Epaulette Surgeonfish or Eyeline Surgeonfish, is an impressive saltwater fish distinguished by its deep, streamlined body and bold shoulder marking. Adult coloration ranges from purplish gray to dark brown, accented by a long black streak behind the eye, a pale band at the base of the tail, and subtle blue edging along the fins. Its understated pattern becomes especially striking as the fish moves through a brightly illuminated marine aquarium.

Native to the tropical Indo-Pacific, Acanthurus nigricauda inhabits clear lagoons, protected bays, and seaward reef environments from East Africa to the Tuamotu Islands. Unlike many surgeonfish, it is commonly associated with sandy bottoms and isolated coral or rock formations rather than dense coral growth. Adults may approach 18 inches and require substantial room for continuous swimming and grazing.

Although generally less combative than some members of the genus Acanthurus, the Epaulette Tang remains a large, active, and potentially territorial marine aquarium fish. Its impressive adult presence and distinctive markings make it an excellent centerpiece for a spacious reef aquarium or fish-only aquarium maintained by an experienced aquarist.

Quick Care Guide

Care Level: Moderate
Minimum Tank Size: 250 gallons
Temperament: Semi-aggressive
Diet: Herbivore/Detritivore
Reef Safe: Yes
Region: Indo-Pacific, from East Africa to the Tuamotu Islands; north to the Ryukyu Islands and south to the Great Barrier Reef
Scientific Name: Acanthurus nigricauda

Tank Requirements

Provide a long, wide aquarium with extensive open swimming space. Rockwork should be arranged to create broad swimming lanes while still offering caves, overhangs, and secure nighttime retreats. Avoid filling the center of the aquarium with dense rock structures that restrict movement.

A mature system with natural algal films on the rockwork will provide valuable grazing opportunities. A mixed aquascape incorporating rock, open sand, and scattered coral structures reflects the bays and lagoons this species naturally occupies.

Moderate to strong, varied water movement is recommended, along with vigorous surface agitation and efficient filtration. Surgeonfish have high oxygen requirements, so dependable circulation, protein skimming, and stable water quality are particularly important.

All rock structures should be securely positioned. This is a powerful, active fish that can disturb unstable decorations as it swims or retreats into shelter. The aquarium should also have a secure lid or canopy to prevent accidental jumping.

Diet and Feeding

In the wild, the Epaulette Tang grazes on thin algal films growing over sand, rubble, and rock. Much of its natural nutrition comes from organic detritus trapped within these films rather than from algae alone.

In captivity, offer dried marine algae or nori every day. Supplement this with spirulina-based flakes, quality herbivore pellets, frozen marine herbivore blends, and preparations containing marine algae. Allowing some natural algae to develop on the rockwork encourages normal grazing behavior.

Small amounts of mysis shrimp, enriched brine shrimp, chopped seafood, or other meaty marine foods may be included for variety, but these should not replace the plant-based portion of the diet. Feed two to three small meals daily and keep seaweed available for extended grazing whenever practical.

Multiple feeding clips can reduce competition when the fish is housed with other large herbivores.

Temperament and Tankmates

The Epaulette Tang is semi-aggressive. It is often more tolerant of unrelated fish than highly territorial surgeonfish such as the Clown Tang, but individual behavior varies. A mature specimen may become increasingly assertive as it grows and establishes a territory.

Keep one Epaulette Tang per aquarium. It may challenge other surgeonfish, especially similarly shaped members of the genus Acanthurus. Combining it with additional tangs should only be attempted in exceptionally spacious aquariums with separate territories, abundant food, and careful introduction planning.

Suitable tankmates include larger angelfish, rabbitfish, substantial wrasses, peaceful triggerfish, groupers appropriate for the aquarium, and other confident marine fish. Small, passive species may be intimidated by its size and activity even when they are not directly attacked.

When adding this species to a community, introduce less assertive fish first whenever possible. Rearranging portions of the rockwork before introducing another large tang may help disrupt established territories, but it cannot guarantee compatibility.

Reef Compatibility

The Epaulette Tang is generally considered reef safe. It normally grazes on algae, biofilm, and organic material rather than feeding on healthy corals. Ornamental shrimp, crabs, snails, clams, and other established reef invertebrates are not typically targeted.

A poorly fed specimen may investigate sessile invertebrates or repeatedly graze around coral bases while searching for algae. Providing frequent meals and ample grazing surfaces helps minimize unwanted picking.

Its main limitations in a reef aquarium are its adult size, swimming requirements, and possible aggression toward other fish rather than coral predation.

Water Parameters

Temperature: 75–80°F
Specific Gravity: 1.024–1.026
pH: 8.1–8.4
Alkalinity: 8–12 dKH

Prioritize stable salinity, temperature, and pH over repeatedly adjusting the aquarium to reach an exact number. Strong oxygenation and consistently low levels of dissolved waste are essential for long-term health.

Common Considerations

Can approach 18 inches and requires an exceptionally spacious, long aquarium.
May become territorial toward other tangs and similarly shaped marine fish.
Requires daily marine algae and frequent opportunities to graze.
Benefits from strong circulation, vigorous oxygenation, and efficient filtration.
Possesses a sharp caudal-peduncle spine that can injure handlers or other fish.