Purple Tang,
Zebrasoma xanthurum

Photos courtesy of melev, Dustin2, and ReeferArt

Common Name: Purple Tang, Yellowtail Surgeonfish, and Yellowtail Tang
Scientific Name: Zebrasoma xanthurum
Size: Up to 22 cm (10 inches)
Distinguishing Features: Yellow on tail as well as fins; the main body purple. Juveniles tend to have horizontal striping that eventually fades away. Body shape is similar to a Sailfin tang, most obvious when the fish displays its fins when startled, in defense or aggression.
Origin: Originally described in the Red Sea (Blyth, E. 1852). This species has spread as far east as the southern region of the Persian Gulf.
Natural Habitat: Found in coral thriving regions or on rocky slopes of the Red Sea from depths of 2-20 meters.
Feeding Requirements: The Purple Tang is omnivorous, grazing upon algae as well as accepting flake, frozen, and dried foods. For proper care, vegetable based flake or dried seaweed introduced regularly into the aquarium is ideal. Seaweed of acceptable grade can commonly be purchased from an orient grocer and in some supermarkets.
Difficulty Rating:
(1 = easy - 5 = hard)
3 – Providing stable temperature, stable salinity, strong water flow, and room for them to swim freely this tang can be extraordinarily resilient. Most difficulty comes with fish compatibility as this is suggested as the last addition to an aquarium due their territorial nature.
Aggressiveness Rating:
(1 = shy - 5 = nasty)
4 - Generally a peaceful fish with other established tankmates, the Purple Tang can become aggressive with new additions especially similar tang species. Tangs should be introduced at the same time to avoid fighting. Other similar niche fish should be introduced prior or at the same time to avoid conflict.
Captive Requirements: Temperature range: 24 – 28°C (75 – 82oF) Specific Gravity: 1.020-1.025; pH 8.1-8.4. Tangs require swimming room and should not be kept in aquariums less than 100 gallons.
Optional Requirements: Purple Tangs inhabit rockier regions of the Red Sea. They hide under rockwork for safety and to sleep at night. Providing similar conditions will help to promote successful husbandry of this beautiful specimen.
Reef Tank Compatibility: Purple Tangs do well in Fish Only with Live Rock (FOWLR) and are compatible with reef aquariums. Will swim throughout the day looking for foods, picking on filamentous algae. However, they have been noted to pick at LPS.
Notes: Purple Tang health is an important factor when purchasing, as shipping can be hard on this specimen. Make sure the tang is full-bodied, with deep purple/yellow two-toned coloration, and constantly swimming.
Head and Lateral Line Erosion (HLLE) disease is commonly reported in this species. Open wounds will appear around the head or around the lateral line across the body of the fish. Increasing water quality as well as providing supplemental vitamins, such as macroalgae or food soaked in Selcon will help aid in recovery.
Further Reading: WetWebMedia.com - Z._xanthurum
Fishbase: Purple Tang
About.com - HLLE Disease
Marine Head and Lateral Line Erosion, by Steven Pro

Note: All of the above information has been compiled from various sources and should be used as a guideline, not a hardfast rule. Use caution when selecting animals for your own tank and research as much as possible before purchasing any animals. Remember that certain corals and fish are very hard to keep if their special requirements are not met. The information contained here is to help you make an informed decision. The author assumes no responsibility for any consequences that may arise from the use of this information.

Fish Profile: Purple Tang, Zebrasoma xanthurum by Nathaniel Walton - Reefkeeping.com