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Even though Purple Tangs are a bit pricey and somewhat aggressive, they are beautiful and rewarding fish species to keep in a saltwater aquarium. Their bright colors and large size allow them to quickly stand out among other fish, you just have to make sure to have a large enough tank and ideally not more than one Purples.

This guide covers everything you need to keep your Purple Tangs healthy from diet, tank size to mates, breeding and behavior. Enjoy! 

Species Summary

Purple Tangs (Zebrasoma xanthurum) are a unique species that many aquarists value because their striking coloration makes them stand out among their fellow reef inhabitants. These fish are members of the Surgeonfish or Acanthuridae family. There are 38 total species of Tangs.

Purple Tangs are native to, and most abundant in, the coral reefs of the Red Sea, but they exist in smaller numbers in the Arabian Sea, the western Indian Ocean, the Gulf of Aden, and the Persian Gulf. They spend most of their time around 65 feet below the surface, combing for algae and food. Purples are active during the day and take shelter among the rocks at night.

Also known as Yellow-tail Surgeonfish and Blue Surgeonfish, Purple Tangs are solitary omnivores. The species is considered aggressive. They will fight when threatened or feel other Tangs encroaching on their territory. Despite this reputation, they function well in community tanks with adequate space for swimming and experience minimal stress.

Author Note: These Tangs are also one of the more expensive reef fish, making them better for experienced aquarists with mature tank setups. While easy to adapt to a simulated diet, they are not as durable as many other reef species due to their lack of strong immune systems.

Appearance

Unsurprisingly, Purple Tangs have purple bodies. Some specimens have a deep blue or indigo shade, but this coloration is relatively uncommon. Accenting the Tangs’ vivid purple hue are the yellow tailfins and, occasionally, yellow-tipped pectoral fins. Purple Tangs have lines across their bodies formed from tiny black dots. In some specimens, the lines are barely perceptible due to the fish’s deep purple color.

Tangs have flat, disc-shaped bodies with rounded bellies. Their coloration will fade if they experience stress or illness. This change signals that you must assess the water quality and your fish’s well-being.

Tangs’ eyes sit high on either side of the head. They have extended snouts with 20 upper teeth and 22 lower teeth that resemble spatulas, helping the fish complete its daily grazing for microalgae and macroalgae.

Purple Tangs have lengthy dorsal and anal fins relative to their size. With the fins extended, the fish is as tall as it is long when measured from tip to tip. Like other members of the Tang family, Purples have two spikes descending from either side of their caudal peduncle, the area between their anal fins and tail fin.

They use the appendage for self-defense and skirmishes with other Tangs over territory. This spike resembles a scalpel, giving members of the family the Surgeonfish moniker.

Lifespan

A wild Purple Tang has a lifespan of 30 to 45 years. Marine biologists can track their lifespans because, like human fingerprints, each Tang has a unique pattern formed by its black dots, making it easy to identify and track individual fish.

Purple Tangs in captivity can live up to 10 years with the proper care and optimal tank conditions. Juveniles are a dark blue color with grey striping and yellow tailfins. They darken as they mature.

Average Size

Captive Purple Tangs have an average size of 8 to 10 inches. Males are slightly larger than females. These fish reach maturity at three to five years. They are available for sale when they are as little as 2.5 inches long.

Purple Tang Care

The primary challenges to caring for Purple Tangs are accommodating their size and preventing disease. Active surveillance and maintaining consistent water conditions are vital. Most aquarists consider Purple Tangs moderately difficult to care for. It’s essential to factor in price when deciding if a Tang is a good option for your aquarium. Juveniles from reputable retailers cost over $100.

Tank Size

Experts recommend a minimum tank size of 100-gallons due to Purple Tangs’ relatively large size and active nature. As will most fish, the biggest tank possible is ideal. Tangs are territorial with members of their species, so a much larger tank is needed if you hope to keep a pair. However, most aquarists elect to keep only a single Tang because the cost is too high to risk a potentially fatal fight between two Purples.

Author Note: Tangs are active swimmers who need space and room to explore. When they feel confined or crowded, their aggressive nature amplifies, increasing the chance of a violent confrontation with one of their tank mates.

Water Parameters

• Water temperature: 74 to 82°F
• pH levels: 8.1 to 8.4
• Water hardness: 8 to 12 dKH
• Specific gravity: 1.020 to 1.025

Tank Setup

The key to knowing what to put in the tank is finding a balance between providing adequate space for Purple Tangs to swim while also allowing them to hide. Therefore, your tank needs enough open water for these active swimmers to explore and plenty of rock with crevices and hiding spots where the fish can sleep at night.

Corralling and moving your Tang with a bucket is the best method to transfer them between tanks. Their spikes can become easily tangled in nets, increasing the chance of injury to the fish or your hand.

Tangs need plenty of live rock with openings large enough to hide within at night. This setup is essential for managing stress and keeping the fish happy. While Tangs are not burrowers, a fine sandy substrate is best. When stressed, Purples will dig into the tank floor. If the substrate is too coarse, they can easily injure their bodies.

Author Note: These fish will leap from the tank, making a secure lid vital to keeping them.

Lighting

Though an active daytime fish, wild Tangs spend most of their time far below the ocean surface. Regular tank lights are enough to provide Tangs with their preferred illumination. Utilizing a timer to establish a consistent day-night cycle for your Tang helps keep them at ease.

Filtration

You need a filter that can handle your tank volume. While a larger aquarium will tank longer to reach ammonia and nitrate levels that can harm most fish, Tangs are sensitive to water changes. In addition, creating a strong water current using a power head will maximize your fish’s quality of life. The conditions provide the fish with satisfying resistance to swim against and enhance the oxygen available in the water.

Acclimation 

Most specimens are wild-caught, though cultivated fish are becoming more common. The species often suffers from Marine Ich, making it essential to isolate your fish before introducing it to your tank. Best practices require a quarantine tank.

First, adjust your Tang to conditions in the destination tank using the slow drip method for at least an hour. Then introduce them to the quarantine tank and begin routine care. Monitor your Tang for white markings that characterize the disease. Experts suggest keeping your Tang quarantined for two weeks to one month before adding them to your tank.

Are Purple Tangs Reef-Safe?

Yes. Not only are Purple Tangs reef-safe, but they consume hair algae, which grows among coral and can be hard to manage. Despite their reputation as feisty fish, Purples will not damage coral polyps or upset rock unless they feel stress or agitation. If you observe this behavior, assess the fish’s nutrition and check for signs of disease.

Common Possible Diseases & Prevention

Unlike many other reef fish, Purple Tangs do not produce the protective slime that offers anti-microbial protection. As a result, they are more susceptible to Marine Ich, Head and Lateral Line Erosion, and parasitic infections than fellow fishes. Wild Tangs rely on cleaner fish to cleanse them of potentially harmful microbes. Captive fish will not necessarily accept the same behavior from tank mates like Wrasses because space limitations enhance the Tangs’ innate aggression.

Author Note: Marine Ich is a common infection characterized by white splotches across the body. The illness causes lethargic behavior. Breathing problems are also a common issue. If you note Marine Ich, you should quarantine your Tang and begin treatment with over-the-counter anti-parasitic medication.

Purples are also highly susceptible to Head and Lateral Line Erosion, a disease resulting from malnutrition. The condition causes fish to develop open wounds on their head or across the lateral aspects of their body as tissue breaks down.

It is treatable if caught early but is commonly fatal. You can manage the disease by improving water quality to optimal ranges and administering supplemental vitamins, macroalgae, and foods soaked in Selcon.

Stress compromises Tangs’ health and wellness, making it critical to only house them in large tanks with adequate space and consistent water conditions.

Food & Diet

While omnivorous, Purple Tangs’ diet tends to be towards plant-based food sources. In the wild, they primarily eat filamentous algae. These fish are voracious eaters due to their large size and active nature. As a result, you must supplement the available tank algae with other food.

Experts recommend providing clipped nori by inserting bits into the rock formations and supplying extra algae grown in a refugium. You should provide enough food for two to three daily grazings and monitor your fish’s body shape to ensure it’s getting enough nourishment. Despite their long, flat shape, healthy Tangs have slightly plump bellies.

Providing protein is also essential for helping your Tang meet its caloric needs. They are not picky eaters, so try Brine shrimp, protein-based flakes, and Mysid shrimp to see what your Tang prefers. A varied diet also helps keep the fish healthy and active.

You can also offer an occasional mature rock covered in macroalgae as a treat for your Tang.

Behavior & Temperament

Wild Purple Tangs form schools as they mature and are generally easy-going creatures. The confines of your tank will bring out their innate aggression. Captive Tangs are curious and active swimmers who comb each inch of your tank to satisfy their constant hunger.

Some owners attempt to house multiple Tangs together before they reach maturity, believing their familiarity will prevent aggression as they develop together. The cost of Purple Tangs and their propensity toward violence make raising more than one Tang risky. Tangs will use their spikes to fight one another and may even attack other species of Tangs with similar shapes.

Purples are highly-active swimmers who will cover all levels of your tank and search for food. As long as the tank has adequate space, they do not interfere with other fish. When first introduced to your tank, they may spend more time than usual hiding as they adjust. Once they establish themselves, they are often skeptical of new tank mates. Be sure to actively monitor all fish for signs of injury when introducing additional fish.

Author Note: Biologists estimate that Purples spend up to 70% of their day grazing. In captivity, they will eat algae around the tank and readily accept almost any plants you offer. Interestingly, these fish have unusually long digestive tracts, which enable them to spend so much time eating.

Purple Tang Tank Mates

Despite their reputation, Purples can reside peacefully with many other reef fish. However, avoid shy and passive species because your Purple’s seemingly hyperactive nature can stress and intimidate docile tank inhabitants. Solid options for tank mates include:

• Blood Red Fire Shrimp (a higher grade of the Cherry Shrimp)
• Blue-Green Chromis
• Coral Beauty Angelfish
• Foxface Rabbitfish
• Lyretail Anthias
• Majestic Angelfish
• Neon Gobies
• Skunk Cleaner Shrimp
• Tomato Clownfish
• Wrasses

Breeding

Home breeding of this species is impossible. Beyond the cost of the fish, they are broadcast spawners, requiring large commercial tanks to mate. This mating process involves a member of each sex releasing its reproductive material into the water and allowing the current to bind it together for fertilization.

In addition, they are virtually impossible to sex, making it difficult to establish a breeding pair. Tangs’ small geographic concentration and the difficulty of even commercial breeding contribute to the high cost of these fish.

Conclusion

Caring for a purple tang requires a commitment to providing a healthy and stable environment. From ensuring high water quality to providing a varied and nutritious diet, there are many factors to consider when caring for these beautiful fish. However, the rewards of seeing these graceful fish swimming in a healthy and thriving environment can be well worth the effort.