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Ringtail tang

Acanthurus blochii (Ringtail Tang / Ringtail Surgeonfish / Dark Surgeonfish)

Small fish safe: ✅ Yes

Small invert safe: ✅ Yes

Coral safe: ✅ Yes

Minimum tank size: 1,000 liters (265 gallons)

Adult size: Up to 50 cm (20 inches)

Diet: Primarily herbivorous; requires a diet rich in marine-based seaweed and algae

Be aware of: Can be territorial, especially towards conspecifics; requires ample swimming space and a well-established aquarium with abundant live rock for grazing

Ringtail Tang (Acanthurus blochii) – A Majestic and Active Reef Inhabitant

The Ringtail Tang, also known as the Ringtail Surgeonfish or Dark Surgeonfish, is a large and striking member of the surgeonfish family. Its vibrant coloration and active swimming behavior make it a captivating addition to spacious marine aquariums.

Appearance and Coloration

The Ringtail Tang boasts a distinctive and colorful appearance:

Body Color: Bluish-grey accented by yellow-brown spots running longitudinally across its body.

Eye Area: Often displays a little yellow around the eye with a yellow spot just behind the eye.

Tail: A white ring around the base of its tail lends it the common name “Ringtail Tang.”

These vibrant features make the Ringtail Tang a standout specimen in large marine aquariums.

Natural Habitat and Behavior

In the wild, Ringtail Tangs are typically found in:

Habitat: Outer lagoons and seaward reefs, often at depths ranging from 2 to 15 meters.

Geographical Range: From the East African coast to the Hawaiian Islands, encompassing the Indian and Pacific Oceans.

Behavior: They usually form small groups but can also form large schools in certain locations.

In captivity, they require ample space to swim and graze, as well as plenty of live rock to establish territories and provide grazing surfaces.

Tank Requirements and Water Parameters

Due to their size and active nature, Ringtail Tangs require a spacious and well-maintained aquarium:

Minimum Tank Size: 1,000 liters (265 gallons)

Temperature: 23–26°C (73–79°F)

pH: 8.0–8.3

Salinity: Specific gravity of 1.020–1.025

Water Movement: Moderate to strong, replicating natural reef conditions

Aquascaping: Ample live rock to create hiding spots and grazing areas, while ensuring open spaces for swimming

Maintaining high water quality and stable parameters is essential for their health and well-being.

Diet and Feeding

As herbivores, Ringtail Tangs require a diet rich in marine-based vegetation:

Primary Diet: Marine-based seaweed and algae

Feeding Frequency: Offer dried seaweed tied to a rock or use a veggie clip at least three times per week.

Recommended Products: Sea Veggies, Seaweed Salad, and Ocean Nutrition are ideal options. 

A diet rich in marine algae will strengthen their immune system, reduce aggression, and improve overall health.

Compatibility and Tank Mates

Ringtail Tangs are generally peaceful but can exhibit territorial behavior, especially towards conspecifics:

Compatible Tank Mates: Most community saltwater fish that are non-aggressive and dissimilar in appearance

Caution With: Other tangs or surgeonfish, especially those of similar shape or coloration, unless housed in a sufficiently large aquarium

Introducing them into a well-established tank with ample space can help mitigate territorial behaviors.

Health and Disease Considerations

Ringtail Tangs are relatively hardy but can be susceptible to common marine diseases:

Marine Ich: Maintain optimal water quality and a nutritious diet to prevent outbreaks

Head and Lateral Line Erosion (HLLE): Associated with poor water quality and inadequate nutrition; ensure a balanced diet and pristine conditions

Regular monitoring and maintaining optimal water conditions are essential for their well-being.

Lifespan and Long-Term Care

With proper care, Ringtail Tangs can live for several years in captivity. Their longevity is enhanced by providing a spacious environment, a balanced diet, and regular health monitoring.

Why Choose a Ringtail Tang?

Algae Control: As natural grazers, they assist in managing algae growth within the tank

Visual Appeal: Their distinctive coloration and active behavior make them a captivating addition to marine aquariums

Hardiness: With proper care, they adapt well to captive environments and can thrive for many years

The Ringtail Tang is a beneficial and attractive choice for aquarists seeking both aesthetic appeal and functionality in algae management.