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Zebrasoma xanthurum, Purple Tang. Alf Jacob Nilsen/Bioquatic Photo


Also known as the tangs or doctorfishes, the surgeonfishes are laterally compressed and have a continuous dorsal fin, a small, terminal mouth with spatulate, acute, or brushlike teeth, and a modified spine or spines on the side of the caudal peduncle. All the surgeonfishes have long intestines, and some have a gizzardlike stomach that facilitates mastication of food materials.

There are three subfamilies, whose members are easily distinguished by the number and morphology of the caudal peduncle spines.

  • The Subfamily Nasinae, the unicornfishes, has one or two fixed spines.
  • The Subfamily Prionurinae has three to ten bony plates on the side of the caudal peduncle.
  • The Subfamily Acanthurinae has a single spine that folds into a groove on the side of the caudal peduncle.

The majority of the members of all three subfamilies occur on or adjacent to coral reef habitats. Some live in warm temperate seas, and these species normally inhabit rocky reefs. Most of the surgeonfishes are detritivores and/or herbivores, but the types of plant material consumed and the feeding behavior of each species varies within the family.

For example, some suck detritus and diatoms off the sand, some browse on macroalgae, and others graze on unicellular algae growing on hard substrates. Surgeonfishes may defend a feeding territory, pairs may roam over a large home range, or roving shoals may form that swamp the defenses of territorial species.


Native range:

Taxonomic rank: Family

Common name: Surgeonfishes, Tangs, Unicornfishes

Total known Total profiles
Subfamilies 0 0
Genera 6 5
Species 72 13

Captive care: Surgeonfishes constitute one of the most popular groups of marine aquarium species. They vary somewhat in their husbandry requirements and hardiness, but most need large quantities of plant material every day, a large-sized aquarium, and lots of swimming room. Be sure to know the maximum length attained by any species being considered for purchase (some surgeonfishes get too large for the average home aquarium).

Provide suitable hiding places, including a “bolt hole” (a hiding place they can dash into if threatened). Provide brisk current and well-oxygenated water. Many surgeonfishes behave aggressively toward other fishes, especially other herbivores introduced after the surgeonfishes are established in the aquarium. It is risky to keep members of the same species together in the same tank. Unless you have a large tank and are an experienced aquarist, keep no more than one member of the family per tank.

Feeding: Offer a diet that consists primarily of vegetable matter, including dried and frozen marine algae and leafy green lettuce. Feed several times a day, or secure pieces of dried macroalgae (i.e., nori) to the side of the tank with a lettuce clip. Other Advice: Surgeonfishes, mostly from the genus Zebrasoma, are often employed to control undesirable algal growth in reef aquariums. Most reef aquarists have success with this arrangement, but acanthurids will also consume decorative macroalgae, and some species are prone to picking at sessile invertebrates like large-polyped stony corals.

Notes: The surgeonfishes are susceptible to skin parasites. Because these fishes have sharp spines on the caudal peduncle, use care in handling them; large specimen containers are advised for capturing any surgeonfish to avoid having them become entangled in the mesh of an aquarium net.