Description:

The Double Saddled Butterflyfish, scientifically known as Chaetodon ulietensis (also sometimes called Pacific Double-Saddle Butterflyfish or False Falcula Butterflyfish), is a distinct and attractive species within the butterflyfish family. It shares some visual similarities with the Saddled Butterflyfish (Chaetodon ephippium) but has its own unique characteristics and care requirements.

Description and Appearance:

• “Double Saddle” Markings: The most distinguishing feature is the presence of two prominent black “saddle” markings on its upper back, one towards the head and another near the tail. These saddles are typically bordered by a white or lighter band.
• Coloration: The body is generally white to pale yellow, with thin, vertical black lines that become more pronounced towards the posterior. The posterior portion of the body, including the caudal peduncle and the tail fin, is a vibrant yellow. There’s also a black vertical band passing through the eye.
• Size: They typically grow to about 15-20 cm (6-8 inches) in length, making them a medium-sized butterflyfish.

Natural Habitat:

• Geographic Range: The Double Saddled Butterflyfish is found throughout the central Indo-Pacific region, from the Cocos-Keeling Islands to the Tuamotu Islands, and north to Japan. It’s also found around Australia, including the Great Barrier Reef.
• Environment: They inhabit shallow coral reefs and lagoons, often in coral-rich areas. They can be found individually, in pairs, or sometimes in small groups.

Care Requirements for the Aquarium:

• Care Level: Moderate to Difficult. While generally considered hardier than some other butterflyfish species, they still require a well-established and stable marine aquarium. Getting them to consistently feed on prepared foods can be a challenge initially.
• Tank Size: A minimum tank size of 190-340 liters (50-90 gallons) is recommended for a single Double Saddled Butterflyfish. For a pair or if housing with other fish, a larger tank (e.g., 475 liters / 125 gallons or more) is highly advisable to provide ample swimming space and reduce territorial disputes.
• Aquascape: Provide plenty of live rock with numerous hiding spots, caves, and crevices for security. They also appreciate open swimming areas.
• Water Parameters:
  • Temperature: 24-28C (75-82F)
  • pH: 8.1-8.4
  • Salinity (Specific Gravity): 1.020-1.025
  • Water Quality: Maintaining pristine water quality is crucial. Undetectable ammonia and nitrite, and very low nitrates are essential. A robust filtration system, including a good protein skimmer, is a must.
• Water Flow: Moderate water flow is generally preferred.
• Lifespan: With proper care, they can live for 5-8 years in captivity.

Diet and Feeding:

• Omnivore with Coral/Invertebrate Tendencies: In the wild, their diet consists of a mix of coral polyps, small benthic invertebrates (worms, crustaceans), algae, and zooplankton. This natural feeding habit is the main reason for caution in a reef tank.
• Captive Diet: A varied and consistent diet is vital.
  • Offer high-quality marine flake and pellet foods as a staple.
  • Supplement heavily with frozen foods such as mysis shrimp, vitamin-enriched brine shrimp, finely chopped seafood (clams, mussels, squid), and marine algae/seaweed sheets (nori, spirulina).
  • They will also graze on microalgae and small invertebrates found on live rock.
• Feeding Frequency: Feed small amounts 2-3 times daily for adults, and more frequently for juveniles or newly introduced individuals to ensure they get enough nutrition.

Temperament and Compatibility:

• Generally Peaceful: Double Saddled Butterflyfish are usually peaceful towards most other fish species.
• Territorial towards Similar Species: They can become territorial or aggressive towards other butterflyfish, especially those with similar body shapes or patterns. It’s generally best to keep only one Double Saddled Butterflyfish per tank unless you have a very large aquarium and can introduce a confirmed mated pair simultaneously.
• Reef Safe: No, they are generally NOT considered reef safe. This is a critical factor. While they are not as strictly corallivorous as some other butterflyfish, they are known to nip at and consume soft corals, stony coral polyps (LPS and SPS), anemones, and other sessile invertebrates like tube worms. They are best suited for FOWLR (Fish Only With Live Rock) aquariums where their coral-nipping won’t be an issue. Some sources mention they may target dead or overgrown parts of corals, but occasional nipping at healthy corals is also possible.
• Tank Mates: Compatible tank mates include other peaceful to semi-aggressive fish that won’t outcompete them for food or stress them. Examples include:
  • Clownfish
  • Gobies
  • Cardinalfish
  • Tangs (in sufficiently large tanks)
  • Peaceful wrasses
  • Certain angelfish (monitor for compatibility)

Special Considerations:

• Acclimation: Purchase a specimen that is already actively feeding in the store. Smaller juveniles can be more delicate during acclimation.
• Quarantine: A quarantine tank is highly recommended to observe their feeding habits and monitor for any signs of disease before introducing them to your main display.
• Copper Sensitivity: Like many butterflyfish, they can be sensitive to copper-based medications, so use them with caution and only if absolutely necessary.
• Aiptasia Control: Some individuals have been reported to eat Aiptasia (glass anemones), which can be a beneficial trait in a FOWLR tank. However, this is not a guaranteed behavior for all individuals.

The Double Saddled Butterflyfish is a beautiful and engaging fish, but its size and natural diet make it a demanding species best suited for experienced aquarists with FOWLR setups where its unique behaviors and beauty can be appreciated without endangering a coral reef environment.

Compatibility Information