Shoulder Tang (Acanthurus olivaceus)

Description

Orange Shoulder Tang (Acanthurus olivaceus)

Overview

• Scientific Name: Acanthurus olivaceus
• Common Names: Orange Shoulder Tang, Orangebar Tang, Orange-Epaulette Surgeonfish, Olive Tang
• Origin: Indo-Pacific (East Africa, Maldives, Indonesia, Philippines, Hawaii, Australia, Polynesia)
• Adult Size: Up to 14 inches (35 cm); typically 10-12 inches in captivity
• Lifespan: 10-15 years in aquariums; potentially 30-45 years in the wild
• Care Level: Moderate
• Temperament: Semi-aggressive, territorial toward similar species
• Reef Safe: Yes, but may nip at LPS/soft corals if underfed
• Availability: Common in the aquarium trade; mostly wild-caught, with limited aquacultured specimens

The Orange Shoulder Tang is named for the vivid orange patch near its pectoral fins, which develops in adults (juveniles are bright yellow with faint markings). As a member of the Acanthuridae family, it possesses a sharp caudal spine (“scalpel”) used for defense, requiring careful handling. Its algae-eating habits make it a functional addition to reef tanks, but its large size and territoriality demand a spacious setup and proper tank mate selection.

Care Requirements

Orange Shoulder Tangs thrive in environments mimicking their natural reef habitats, with strong water flow, stable parameters, and ample grazing surfaces. They are susceptible to marine ich and head/lateral line erosion (HLLE) if stressed or poorly fed, so water quality and diet are paramount.

• Tank Size    Minimum 125 gallons (475 liters); 180+ gallons preferred    Juveniles can start in 100 gallons, but upgrades are essential. Space reduces stress and aggression.
• Temperature    72-82°F (22-28°C)    Ideal 75-78°F; use heater/chiller for stability.
• pH    8.1-8.4    Maintain stability to avoid stress; test weekly.
• Salinity (SG)    1.020-1.025    Standard marine salinity; use refractometer.
• Water Hardness    8-12 dKH    Buffers pH; use marine salt mixes.
• Ammonia/Nitrite    0 ppm    Critical; poor water quality leads to disease.
• Nitrate    <20 ppm    Keep low via 10-20% weekly water changes.
• Lighting    Moderate to high    Supports algae growth; 8-10 hours/day with LEDs or T5.
• Filtration & Flow    Strong; 20-40x tank volume/hour    Protein skimmer, powerheads, live rock for biological filtration.

Aquascaping: Provide live rock for grazing and hiding, with open swimming areas. Use secure structures to prevent dislodging by active swimming. A jump guard is recommended, as tangs may leap when stressed.

Acclimation: Drip acclimate over 1-2 hours to prevent shock. Quarantine for 2-4 weeks to monitor for parasites like ich or flukes.

Health Notes: Prone to ich (white spots), HLLE (erosions on head/lateral line), and bacterial infections. Use UV sterilizers and quarantine with copper-based treatments if needed.

Maintenance

Regular maintenance prevents health issues and maintains vibrant coloration.

• Water Changes: 10-20% weekly using RO/DI water matched to tank parameters.
• Filtration: Employ a protein skimmer, canister filter, or refugium. Add activated carbon to remove toxins.
• Testing: Weekly monitoring of pH, salinity, ammonia, nitrite, nitrate, and phosphate using reliable kits.
• Cleaning: Siphon detritus during water changes; clean filters monthly. Monitor algae growth, as the tang grazes but requires supplemental feeding.
• Handling: Use caution due to sharp caudal spines, which can cause injury. Transfer using a container, not a net.

Common Issues:

• Marine Ich: Treat in quarantine with copper or hyposalinity.
• HLLE: Prevent with a vegetable-rich diet, low nitrates, and vitamin supplements.
• Aggression: Monitor for bullying; introduce as the last fish to minimize territorial disputes.

Source healthy specimens from reputable suppliers to reduce transport-related stress.

Diet

Primarily herbivorous, Orange Shoulder Tangs graze on filamentous algae in the wild and require a vegetable-heavy diet in captivity to support health, coloration, and temperament. Feed small amounts 2-3 times daily, consumed within 2-3 minutes, to prevent digestive issues or aggression.

Primary Foods:

• Marine algae/nori (e.g., Ocean Nutrition Seaweed Salad, Hikari Sea Veggies).
• Spirulina-enriched flakes or pellets (e.g., New Life Spectrum).
• Blanched vegetables: Zucchini, spinach, romaine lettuce.
• Supplements (10-20% of diet): Frozen mysis shrimp, brine shrimp, or high-quality omnivore flakes/pellets for protein and variety.

Feeding Tips: Use a veggie clip or tie nori to rocks. Provide live rock for natural grazing. Frequent small feedings mimic wild behavior and reduce waste. Brands like Julian’s Thing can target-feed to ensure adequate intake.

A balanced, algae-rich diet enhances the orange shoulder patch and prevents HLLE.

Behavior

Orange Shoulder Tangs are active, diurnal swimmers that graze constantly and may display territorial behavior, particularly toward other tangs or similar-shaped fish. They can change color based on mood, shifting from olive-grey to brighter yellow-brown hues when healthy or excited. Their caudal spine is used defensively and can harm tank mates or handlers.

• Activity Level: High; requires ample swimming space to thrive.
• Social Dynamics: Semi-aggressive; may chase food competitors or similar species. Best kept singly or introduced last to reduce dominance issues.
• Stress Indicators: Glass surfing, hiding, faded coloration, or rapid gill movement—check water parameters and tank mate compatibility immediately.

Compatibility

Orange Shoulder Tangs are generally reef-safe, grazing algae without harming most corals or invertebrates, though hungry individuals may nip at LPS or soft corals. They are best kept as the only tang in the tank unless in a very large system (200+ gallons).

Compatible Tank Mates (in 125+ gallon tanks):

• Robust fish: Clownfish, wrasses, angelfish, hawkfish, larger gobies.
• Invertebrates: Shrimp, snails, crabs, anemones.
• Corals: SPS, most soft corals; monitor LPS with larger specimens.

Incompatible:

• Other Acanthurus tangs (e.g., Achilles Tang) or Zebrasoma species (e.g., Yellow Tang)—leads to aggression.
  Slow or timid fish: Seahorses, pipefish, small anthias.
• Direct food competitors: Rabbitfish, some triggerfish.

Stocking Tips: One tang per 125 gallons. Introduce simultaneously in large tanks to minimize territoriality.

Provide hiding spots to reduce stress.

Reproduction

Breeding Orange Shoulder Tangs in home aquariums is extremely challenging and not feasible for most hobbyists. In the wild, they are broadcast spawners, releasing eggs and sperm in groups or pairs near the surface, with pelagic larvae drifting before settling on reefs.

• Captive Breeding: Rare; no consistent success in home setups due to aggression in pairs and complex larval rearing. Large-scale facilities (e.g., public aquariums) have had limited success with hormone induction and live feeds (phytoplankton, rotifers).
• Sexing: Difficult; males may be slightly larger with white setae near caudal spines; females have larger cloacas.

Hobbyist Notes: Focus on sourcing sustainable wild-caught or aquacultured specimens to support conservation efforts.

Summary

The Orange Shoulder Tang is a vibrant, functional addition to large reef aquariums, controlling algae while showcasing its striking orange shoulder patch. Its care requires a spacious tank, stable water parameters, and a vegetable-rich diet to maintain health and minimize aggression. Intermediate aquarists with experience managing territorial fish and water quality will find it rewarding. Source ethically to support sustainable practices and protect wild populations.

Picture for illustrative purposes only. Either come in store to view available stock or request pictures to be sent to you.

Please Note: Due to variations within species resulting from age, region, sex, etc., the actual livestock may not look identical to the image. Approximate size range may also vary between individual specimens.