Purple Tang: Species Profile & Care Guide

| Updated: June 14, 2023
Purple tang side profile under white lights in a reef aquarium

These beautiful and unique fish can add color and life to your saltwater aquarium. However, they also require proper care and attention to thrive and avoid diseases. In this article, I will provide you with some information about purple tangs, such as their origin, appearance, behavior, diet, tank requirements, compatibility, breeding, and common possible diseases. I hope you will find this article helpful and informative.

What is a Purple Tang?

A purple tang (Zebrasoma xanthurum) is a reef surgeonfish species belonging to the family Acanthuridae. It is also known by other common names such as yellowtail tang, blue surgeonfish, or goldring surgeonfish. First described by zoologist Edward Blyth in 1852.

Origin and Distribution

The purple tang is endemic to the Indian Ocean, where it is found in the Arabian Sea, the Gulf of Aden, the Red Sea, and the waters off Sri Lanka. It usually inhabits coral reefs and lagoons at depths of 3 to 40 meters (10 to 131 feet). The IUCN Red List of Threatened Species considers it a least concern species.

Species Overview

Scientific Name
Zebrasoma xanthurum
Common Names
purple tang, yellowtail tang, blue surgeonfish, goldring surgeonfish
Indian Ocean
Adult Size
10 inches
Life Expectancy
up to 10 years or more
moderate to difficult
Minimum Tank Size
100 gallons
Captive Breedable

Appearance and Identification

The purple tang has an oval-shaped body with a sharp spine at the base of its tail. This spine is one of the defining characteristics of all tangs and surgeonfishes and is used as a weapon for defense or aggression. The body color ranges from blue to purple, with yellow accents on the tail and pectoral fins. The head has black spots and horizontal lines that may vary in intensity depending on the individual. Some purple tangs also have tiny black dots on their body that may blend in with their dark coloration. The dorsal and anal fins are large and when fully extended, they give the purple tang a tall appearance. The eyes are surrounded by a yellow ring that gives this fish its name.

The purple tang can grow up to 25 cm (10 inches) in length. The male is slightly larger than the female and may have a more intense coloration.

Behavior and Temperament

The purple tang is a semi-aggressive fish that can be territorial and dominant over other tangs or similar-shaped fish. It may chase or nip at its tankmates, especially if the tank is too small or overcrowded. It is best to keep only one purple tang per tank unless the tank is very large (over 200 gallons) and has plenty of hiding places and live rock. If you want to keep more than one purple tang, you should introduce them at the same time and provide enough space for each fish to establish its own territory.

The purple tang is also an active and curious fish that likes to swim around and explore its environment. It may occasionally rub its body on rocks or other objects to remove parasites or dead skin cells. It may also display its spine when threatened or excited.

Diet and Feeding

The purple tang is an omnivorous fish that feeds mainly on algae in the wild. It has small, comb-like teeth that help it scrape algae from rocks and coral surfaces. In captivity, it should be offered a variety of foods that include marine-based seaweed, algae, spirulina, mysis shrimp, brine shrimp, krill, plankton, and other prepared foods for herbivorous fish. It should be fed at least twice a day and have access to algae or seaweed throughout the day. Feeding the purple tang a balanced diet will help boost its immune system, reduce aggression, and improve its overall health and coloration.

Tank Requirements

The purple tang is difficult to keep and requires a large, well-maintained saltwater aquarium. Here are some of the tank requirements for this fish:

  • Tank size: The minimum tank size for a single purple tang is 100 gallons (379 liters). A larger tank (150 gallons or more) is recommended for better swimming space and water quality.
  • Water parameters: The water temperature should be between 74°F and 82°F (23°C and 28°C). The pH should be between 8.1 and 8.4
  • The water hardness should be between 8 and 12 dKH. The salinity should be between 1.020 and 1.025 specific gravity.
  • Tank setup: The purple tang needs a tank that mimics its natural habitat as much as possible. It should have plenty of live rock, coral, and other decorations that provide hiding places, grazing areas, and visual stimulation. The tank should also have a strong water flow and aeration to keep the water oxygenated and clean. The purple tang is sensitive to ammonia, nitrite, and nitrate levels, so regular water changes and testing are essential.
  • Lighting: The purple tang does not have any special lighting requirements, but it will benefit from a natural day and night cycle that mimics the sun’s movement. A timer can be used to control the lighting schedule and avoid stress for the fish. The lighting should also be suitable for the corals and other invertebrates in the tank, as they are important sources of food and shelter for the purple tang.
  • Filtration: The purple tang requires a high-quality filtration system to handle its bioload and stabilize the water parameters. A combination of mechanical, biological, and chemical filtration is recommended. A protein skimmer can also help remove organic waste and improve water quality.
  • Acclimation: The purple tang is a delicate fish that changes in water conditions or the environment can easily stress. It is important to acclimate it slowly and carefully to the new tank to avoid shock or disease. A drip acclimation method is preferred, as it allows the fish to gradually adjust to the new water’s temperature, salinity, pH, and other factors. The acclimation process can take several hours or even days, depending on the difference between the old and new water.

Are Purple Tangs Reef-Safe?

The purple tang is generally considered to be reef-safe, as they don’t typically harm corals or other invertebrates in the tank. They may nip at some soft corals, anemones, clams, or feather dusters if they are hungry or bored (not very common). 

They will compete with other herbivorous fish or invertebrates for algae or seaweed. Provide enough food and space for the purple tang and its tankmates and this is often a non-issue. Plus, it’ll help avoid aggression or damage to the reef.

Common Possible Diseases and Their Treatment

The purple tang is prone to several diseases, such as:

  • marine ich
  • lateral line disease
  • parasitic infections
  • bacterial infections
  • fungal infections
  • head and lateral line erosion
  • hole-in-the-head disease
  • fin rot
  • velvet disease
  • pop-eye
  • dropsy
  • swim bladder disease
  • constipation
  • bloat
  • vitamin deficiency

These diseases are often caused by poor water quality, inadequate diet, stress, overcrowding, aggression, or improper acclimation.

The symptoms of these diseases can vary depending on the type and severity of the infection or condition. Some common signs to look for are:

  • White spots or patches on the body, fins, gills, or eyes
  • Loss of appetite or weight
  • Lethargy or abnormal swimming behavior
  • Scratching or rubbing against objects
  • Faded coloration or darkening of the body
  • Cloudy eyes or swollen eyes
  • Redness or inflammation of the skin, fins, gills, or mouth
  • Open sores or ulcers on the body or fins
  • Excess mucus production or slime coat
  • Breathing difficulties or rapid breathing
  • Abdominal swelling or distension
  • Stringy or white feces
  • Erratic movements or loss of balance

Treating these diseases depends on the specific disease and root problem. For more information, check out the articles using the links above or browse here.

Compatibility and Tankmates

Purple tangs are compatible with many other fish and invertebrates as part of a community tank. Of course, some exceptions, like other tangs or similar-shaped fish, can cause territory or dominance disputes. Choose tankmates carefully, and consider their size, temperament, diet, and water requirements. To get you started, here are some of the compatible and incompatible tankmates for the purple tang:

Compatible Tankmates

  • Clownfish: Clownfish are peaceful and colorful fish that can form a symbiotic relationship with anemones in the tank. The purple tang usually ignores them and can coexist peacefully.
  • Angelfish: Angelfish are large and beautiful fish that can add variety and contrast to the tank. They usually tolerate purple tang and share the same food and water conditions.
  • Butterflyfish: Butterflyfish are attractive and peaceful fish that feed on coral polyps, worms, and crustaceans in the tank. They are usually not bothered by the purple tang and can live harmoniously.
  • Blennies: Blennies are small, friendly fish with comical personalities and unique appearances. The purple tang usually welcomes them and can help control algae growth in the tank.
  • Gobies: Gobies are small and colorful fish that have a bottom-dwelling habit and a symbiotic relationship with shrimps in the tank. The purple tang usually leaves them alone and can add diversity and interest to the tank.
  • Wrasses: Wrasses are active and colorful fish that have a varied diet and a cleaning behavior in the tank. The purple tang usually accepts them and can provide benefits to the tank.

Incompatible Tankmates

  • Other Tangs: Other tangs are similar-shaped fish that have a high potential for aggression and competition with the purple tang. They may fight over food, space, or territory, resulting in stress or injury. Some exceptions are yellow tangs (Zebrasoma flavescens) or sailfin tangs (Zebrasoma veliferum), which may get along with the purple tang if they are introduced at the same time and have enough space.
  • Triggerfish: Triggerfish are large and aggressive fish that have a powerful bite and a territorial attitude. They may attack or harass the purple tang, causing damage or death.
  • Puffers: Puffers are large and curious fish that have sharp beaks and toxic skin. They may nip or bite the purple tang, causing injury or infection.
  • Lionfish: Lionfish are large and venomous fish that have long spines and a predatory nature. They may sting or eat the purple tang, causing pain or death.
  • Eels: Eels are large and carnivorous fish that have strong jaw and teeth. They may prey on or bite the purple tang, causing injury or death.

Breeding and Reproduction

The purple tang is a difficult fish to breed in captivity, as it requires specific environmental and social conditions to trigger its mating process. It is also a monogamous fish that forms a pair bond with another purple tang of the opposite sex. The breeding pair will usually isolate themselves from the rest of the tank and perform a courtship ritual involving swimming, circling each other, and changing colors. The female will then release her eggs into the water column, where the male’s sperm will fertilize them. The eggs are pelagic and will drift with the current until they hatch into larvae after 24 hours.

The larvae are very small and transparent and have a high mortality rate due to predation, starvation, or disease. They feed on plankton and other microscopic organisms until they develop into juveniles after 6 to 8 weeks. The juveniles have a different coloration than the adults, as they have a yellow body with blue stripes and spots. They will gradually change their color as they grow and mature.

Interesting Facts About Purple Tangs

  • The purple tang is one of the most expensive and sought-after tangs in the aquarium trade.
  • The purple tang is closely related to other tangs in the genus Zebrasoma, such as the yellow tang (Zebrasoma flavescens), the sailfin tang (Zebrasoma veliferum), and the scopas tang (Zebrasoma scopas).
  • The purple tang can change its color depending on its mood, health, or environment. It can become darker or lighter or show more or less yellow accents.
  • The purple tang can produce a clicking sound by grinding its teeth. It uses this sound to communicate with other fish or to warn off predators or rivals.
  • The purple tang can live up to 10 years or more in captivity if it is well cared for and provided with optimal conditions.

Final Thoughts

The purple tang is a stunning and unique fish that can make a great addition to your saltwater aquarium. However, it is not a beginner-friendly fish, as it requires a large tank, high water quality, a varied diet, and careful acclimation. It is also a semi-aggressive fish that can be territorial and dominant over other fish.

I hope you enjoyed reading this article about purple tangs. If you have any questions or comments, please feel free to leave them below. Thank you for your time and interest. Have a wonderful day! 😊

Shane Elliot Author Image
Shane Elliot

Shane Elliot is a pet lover and a coral enthusiast. He has been keeping saltwater aquariums for over ten years and enjoys sharing his knowledge and expertise with other hobbyists. He writes about coral care, fish compatibility, aquarium equipment, and more. He also covers topics related to other animals, such as dogs, cats, horses, and reptiles. Shane works as a freelance writer and editor when his menagerie of pets allows it.

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