Description:

The Barred Rabbitfish, scientifically known as Siganus doliatus (sometimes referred to as the Two-Barred Rabbitfish or Barred Spinefoot), is a popular and beneficial addition to many larger marine aquariums. It’s known for its striking appearance, excellent algae-eating capabilities, and the unique characteristic of having venomous spines.

Here’s a comprehensive care guide for the Barred Rabbitfish:

Appearance:

• Coloration: They have a distinctive yellow-orange body with a network of fine blue lines that can resemble a “scribbled” or “circuit board” pattern.
• Bars: Two prominent black diagonal bars cross the face: one running through the eye and another just behind the gill plate.
• Fins: The fins are often yellow or orange, complementing the body color.
• Camouflage: Like other rabbitfish, they can dramatically change their coloration to a mottled, splotchy pattern (often brownish or pale) when stressed, sleeping, or trying to camouflage themselves.

Adult Size:

• The Barred Rabbitfish typically reaches an adult size of 10 inches (25 cm) in captivity. Some individuals may grow slightly larger.

Natural Habitat and Distribution:

• Found throughout the Indo-West Pacific Ocean, from Indonesia to Palau, and south to northern Australia (including areas near Queensland) and Tonga.
• Inhabit coral-rich lagoons and seaward reefs, usually at depths between 6 to 50 feet (2 to 15 meters).
• They feed primarily on algae and some benthic invertebrates in the wild. Juveniles often school, while adults typically form pairs.

Aquarium Care (Moderate Level):

• Minimum Tank Size: Due to their adult size and active swimming nature, a minimum of 120-150 gallons (approximately 450-570 liters) is recommended for an adult Barred Rabbitfish. Larger tanks are always better to provide ample swimming room and grazing surfaces.
• Water Parameters: Maintain stable marine water conditions:
  • Temperature: 72-82F (22-28C)
  • Salinity: 1.020-1.025 specific gravity
  • pH: 8.1-8.4
  • Alkalinity (dKH): 8-12 dKH
  • Ammonia and nitrites should be 0 ppm. Nitrates should be kept below 20 ppm.
• Filtration: A robust filtration system is essential to handle their bio-load and maintain water quality.
• Water Flow: Moderate to high water flow is preferred. They are active swimmers and appreciate good circulation.
• Diet:
  • Primarily Herbivorous: Barred Rabbitfish are excellent algae eaters. Their diet should largely consist of marine-based algae and vegetable matter.
  • Offer dried seaweed (nori) tied to a rock or using a veggie clip several times a week (at least 3-4 times).
  • Supplement with high-quality herbivore pellets and flakes, spirulina, and other vegetable-based frozen foods.
  • They may occasionally accept meaty foods like mysis shrimp or brine shrimp, but these should be offered in moderation as their main diet must be plant-based.
  • Feed multiple small meals throughout the day to mimic their natural grazing behavior. They are fantastic at consuming nuisance algae, including hair algae.
• Temperament:
  • Generally Peaceful: Barred Rabbitfish are typically peaceful towards most tank mates, making them suitable for community tanks.
  • Territorial towards other Rabbitfish: They can be aggressive towards other rabbitfish, especially those of the same species or similar appearance. It’s generally best to keep only one per aquarium, unless the tank is exceptionally large (hundreds of gallons) and they are introduced as a mated pair or simultaneously as juveniles.
  • They can hold their own against more aggressive fish due to their venomous spines.
• Reef Compatibility: Reef safe with caution. While they primarily eat algae, if not fed adequately or if very hungry, they may nip at soft corals (like Xenia) and large polyp stony (LPS) corals. Keeping them well-fed significantly reduces this risk. Many hobbyists successfully keep them in reef tanks as excellent algae controllers.
• Tank Setup:
  • Provide plenty of live rock with crevices and hiding spots, as they enjoy exploring and resting among the rockwork.
  • Ensure ample open swimming areas in the water column.
  • A secure, tight-fitting lid is essential as they can jump when startled.
  • A well-established aquarium with existing algae growth is beneficial for their initial feeding.
• Venomous Spines: Crucially, Barred Rabbitfish possess venomous dorsal and anal spines. When threatened or stressed, they can erect these spines. A sting is painful, similar to a bee or lionfish sting, but rarely life-threatening to humans unless there’s an allergic reaction. Exercise extreme caution when performing tank maintenance or handling the fish. If stung, immerse the affected area in hot water (as hot as tolerable, not scalding) as this helps to denature the protein-based venom. Seek medical attention if symptoms are severe or persistent.
• Acclimation: Acclimate them slowly to new tank conditions using a drip acclimation method.