The fish you're likely referring to as the Gold-Rimmed Surgeonfish is scientifically known as Acanthurus nigricans. It is also commonly called the Whitecheek Tang, Velvet Surgeonfish, or Goldrim Surgeonfish.
Appearance:
- They have a deep blue to purplish-blue body.
- A distinctive white or light blue patch is present on the cheek, just behind the mouth.
- The caudal fin (tail fin) is typically light blue with a yellow vertical bar.
- The dorsal, anal, and pectoral fins are dark blue with brighter blue highlights.
- A yellow stripe often runs along the base of the dorsal and anal fins, sometimes forming a "wishbone" shape towards the tail.
Natural Habitat and Distribution:
- Found throughout the Indo-Pacific region, from the Cocos-Keeling Islands and Christmas Island to Southern Japan, south to the Hawaiian Islands and the Great Barrier Reef.
- Inhabit shallow coastal reefs and lower surge zones, typically at depths of 6 to 200 feet (2 to 60 meters).
- They primarily feed on filamentous algae in the wild.
Aquarium Care:
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Minimum Tank Size: Due to their active swimming habits and potential adult size, a tank of 125 gallons (approximately 473 liters) or larger is strongly recommended. More swimming space is always better.
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Water Parameters:
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Temperature: 72-78°F (22-26°C)
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Salinity: 1.020-1.025 specific gravity
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pH: 8.1-8.4
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Alkalinity: 8-12 dKH
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Water Flow: They require strong and turbulent water flow with good oxygenation.
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Diet:
- They are primarily herbivores and require a diet rich in marine-based algae and seaweed.
- Offer a variety of dried seaweed (nori) tied to a rock or using a veggie clip several times a week (at least 3 times).
- Supplement their diet with other vegetable matter like Spirulina, zucchini, broccoli, and leaf lettuce.
- While they may accept meaty foods, these should only make up a very small portion of their diet.
- Small meals 3-4 times a day are better than one large feeding.
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Temperament:
- The Whitecheek Tang is considered semi-aggressive to aggressive, especially towards other tangs or similarly shaped fish.
- It is generally best to keep only one Whitecheek Tang per tank unless the aquarium is very large (hundreds of gallons) and all tangs are introduced simultaneously.
- They can be peaceful with other non-tang species.
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Reef Compatibility: Generally considered reef safe, but if not fed adequately, they may nip at large polyp stony (LPS) corals. They will not typically harm invertebrates.
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Tank Setup:
- Provide plenty of live rock to allow for natural grazing and to offer hiding places.
- Ensure open swimming areas are available.
- A well-established aquarium with stable water parameters is crucial. It's best to introduce them to tanks that are at least a year old.
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Care Level: Considered intermediate to advanced due to their specific needs and potential for aggression and susceptibility to diseases like marine ich if water quality is poor or unstable.
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Acclimation: Proper and slow acclimation (drip acclimation) is essential due to their sensitivity to changes in water chemistry.
Important Considerations:
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Quarantine: It is highly recommended to quarantine new arrivals before introducing them to the main tank to prevent the spread of disease.
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Observation: Closely observe your Gold-Rimmed Surgeonfish, especially during the initial weeks, to ensure they are eating well and adjusting to their new environment.
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Water Quality: Maintaining pristine and stable water quality is paramount for their long-term health.
By providing the appropriate environment, diet, and care, you can successfully keep a Gold-Rimmed Surgeonfish (Whitecheek Tang) in your marine aquarium. However, be prepared for their potential for aggression and ensure your tank is large enough to accommodate their needs.
