Clown Tang

The Clown Tang, also known as the Lined Surgeonfish, is one of the most visually striking saltwater fish available for a large marine aquarium. Its upper body is covered in alternating electric-blue and yellow horizontal stripes edged in black, while the lower body fades into pale blue-gray. Bright yellow-orange pelvic fins and a deeply forked tail complete its unmistakable appearance. Native to shallow, wave-swept reefs across the Indo-Pacific, Acanthurus lineatus is a powerful, almost constantly moving swimmer that naturally grazes throughout the day. Its bold coloration and commanding presence make it an impressive centerpiece for an expansive reef aquarium or fish-only aquarium. Despite its beauty, this is a demanding and highly territorial surgeonfish best suited to experienced aquarists. The Clown Tang requires substantial swimming space, strong water movement, excellent oxygenation, frequent plant-based feeding, and carefully selected tankmates. Quick Care Guide Care Level: Expert Only Minimum Tank Size: 250 gallons Temperament: Aggressive Diet: Herbivore Reef Safe: Yes Region: Indo-Pacific, from East Africa to Hawaii and French Polynesia, north to southern Japan and south to Australia and New Caledonia Scientific Name: Acanthurus lineatus Tank Requirements House the Clown Tang in a long, wide aquarium with extensive open swimming space. Rockwork should provide secure caves and sheltered sleeping areas while leaving broad, unobstructed lanes across the front and upper portions of the aquarium. Strong, turbulent water movement and vigorous surface agitation are important for replicating the oxygen-rich surge zones this species inhabits. Efficient filtration, protein skimming, and consistently high water quality are essential. The aquarium should be mature enough to support natural algal growth on the rockwork for regular grazing. Arrange all rocks securely, as this active and powerful fish can dislodge unstable structures. Long-term housing should account for an adult length approaching 15 inches, its continuous activity, and the large territory it may attempt to control. Diet and Feeding The Clown Tang is primarily herbivorous and should receive a varied, algae-rich diet several times throughout the day. Offer dried marine algae or nori daily, ideally from more than one feeding station in community aquariums. Supplement seaweed with spirulina-based flakes, high-quality herbivore pellets, frozen preparations formulated for marine herbivores, and foods containing marine algae. Occasional mysis shrimp, enriched brine shrimp, or finely chopped marine foods can add variety, but meaty foods should not replace its plant-based diet. Feed small portions two to four times daily when possible. Consistent access to algae supports body condition and reduces competition, stress, and unwanted grazing behavior. Temperament and Tankmates The Clown Tang is aggressive, territorial, and especially intolerant of other surgeonfish. It should normally be kept as the only Clown Tang in the aquarium and is best introduced after more peaceful residents have become established. Avoid housing it with similarly shaped tangs, particularly other members of the genus Acanthurus, unless the system is exceptionally large and managed by an experienced aquarist. Even in spacious aquariums, serious territorial disputes may occur. Choose robust, confident tankmates that are not easily intimidated. Large angelfish, substantial wrasses, triggerfish appropriate for the system, rabbitfish, and other assertive marine fish may be suitable. Small, timid, slow-feeding, or highly passive species can be relentlessly harassed once the tang establishes a territory. Reef Compatibility The Clown Tang is generally considered reef safe. It normally grazes on algae growing across rock surfaces rather than feeding on healthy corals, clams, ornamental shrimp, crabs, snails, or other reef invertebrates. An underfed or nutritionally stressed individual may investigate fleshy coral tissue or repeatedly graze around coral bases. Providing frequent algae-based meals and adequate natural grazing surfaces helps minimize this behavior. Its primary challenge in a reef aquarium is not coral predation but its adult size, activity level, and potential aggression toward other fish. Water Parameters Temperature: 75–80°F Specific Gravity: 1.024–1.026 pH: 8.1–8.4 Alkalinity: 8–12 dKH Maintain strong oxygenation and stable water quality. Avoid sudden changes in temperature, salinity, or pH, particularly during acclimation. Consistency is more important than repeatedly adjusting the aquarium to reach an exact value. Common Considerations Can reach approximately 15 inches and requires an exceptionally spacious aquarium. Highly territorial and often aggressive toward other tangs and similarly shaped fish. Requires strong water movement, high dissolved oxygen, and excellent filtration. Can be sensitive during shipping and initial acclimation; introduce it into a stable, mature system. Possesses sharp caudal-peduncle spines that can cause painful injuries during handling or territorial fights.