The Marquesas Butterflyfish (Chaetodon declivis), also known as the Declivis Butterflyfish, is a captivating marine species recognized for its distinctive coloration and patterns.
Key Information
• Small fish safe: Yes
• Small invert safe: ⚠️ With caution
• Coral safe: No
• Minimum tank size: 454 liters (120 gallons)
• Adult size: Up to 15 cm (6 inches)
• Diet: Omnivorous, feeding on coral polyps, fanworms, crustaceans, tunicates, and algae.
• Be aware of: May nip at corals and small invertebrates; requires a well-established tank with ample live rock for grazing and hiding; can exhibit territorial behavior, especially towards similar species.
Appearance and Coloration
The Marquesas Butterflyfish features a silvery-white body adorned with black spots and a distinctive blackish wedge-shaped area on the upper posterior part of its body. A yellow vertical band runs through its eye, and the dorsal fin is yellowish-orange, while the caudal fin is yellow. This species can reach a total length of up to 12 cm (approximately 4.7 inches).
Natural Habitat and Behavior
Chaetodon declivis is found in the central Pacific Ocean, specifically around the Line Islands, Phoenix Islands, and Marquesas Islands. It inhabits rocky and sandy bottoms at depths between 20 and 60 meters (66 to 197 feet). This species is oviparous, forming pairs during breeding. In the wild, it feeds on coral polyps, fanworms, crustaceans, tunicates, and algae.
Tank Requirements and Water Parameters
To ensure the well-being of the Marquesas Butterflyfish in captivity:
• Minimum Tank Size: A 120-gallon (454 liters) aquarium is recommended to provide ample space for swimming and territory establishment.
• Water Parameters:
• Temperature: 22°C – 26°C (72°F – 78°F)
• pH: 8.1 – 8.4
• Specific Gravity: 1.020 – 1.025
• Aquascaping: Incorporate abundant live rock to create hiding spots and grazing areas, mimicking their natural reef habitat.
• Lighting: Moderate lighting is suitable.
• Water Movement: Moderate flow to simulate their natural environment.
Maintaining stable water conditions and high water quality is crucial for their health. A mature, well-established aquarium with abundant live rock will support their natural grazing behavior and provide necessary shelter.
Diet and Feeding
Marquesas Butterflyfish are omnivorous and adapt well to captive diets:
• Diet: Offer a varied diet consisting of:
• Frozen and freeze-dried foods containing algae
• Dried algae
• Vitamin-enriched brine and mysis shrimp
• Feeding Frequency: Feed small amounts multiple times daily to meet their nutritional needs.
Providing ample live rock will allow natural grazing behavior, which is beneficial for their health and well-being. Initially, they may be shy and reluctant to eat; offering live or frozen foods can encourage feeding until they become accustomed to prepared foods.
Compatibility and Social Structure
Marquesas Butterflyfish can exhibit territorial behavior, especially towards conspecifics and similar species:
• Social Structure: Best kept singly unless in a very large aquarium where multiple individuals can establish territories.
• Temperament: Generally peaceful towards other species but may become aggressive towards similar-looking fish.
• Compatible Tank Mates: Suitable companions include peaceful community fish such as gobies, blennies, and wrasses. Caution is advised when housing with other butterflyfish or species with similar coloration.
Observing their interactions and providing ample space can help mitigate aggressive behaviors. Due to their territorial nature, they should be housed with non-aggressive tank mates to prevent stress.
Important Considerations
• Reef Compatibility: While often considered reef-safe, individual specimens may nip at corals and small invertebrates. Monitoring their behavior is essential, especially in reef setups.
• Acclimation: They may be shy upon introduction but typically become more confident over time.
• Health: Ensure a varied diet and stable water conditions to prevent common health issues.
With proper care and attention to their specific needs, Marquesas Butterflyfish can be a vibrant and rewarding addition to a marine aquarium.