Double Saddle Butterflyfish

The Double Saddle Butterflyfish, Chaetodon ulietensis, is a beautifully patterned saltwater fish distinguished by its pearly white body, fine vertical gray-black lines, and two prominent dark saddle-shaped markings across the upper body. A bold black eye band contrasts with the bright yellow posterior body and fins, while a dark marking near the caudal peduncle completes its unmistakable appearance. It is also commonly known as the Pacific Double-Saddle Butterflyfish or False Falcula Butterflyfish.

Native to the Indo-Pacific, this species inhabits coral-rich lagoon reefs and, less commonly, seaward reef environments. Adults are typically encountered singly, in pairs, or in small groups as they browse reef structure for plant and animal foods. Its active but graceful swimming style and bold contrasting coloration make it an attractive display fish.

Reaching approximately 6 inches as an adult, the Double Saddle Butterflyfish is well suited to a spacious fish-only or fish-only-with-live-rock aquarium. It is considered one of the more adaptable butterflyfish once established, but its natural feeding behavior includes corals and other sessile invertebrates, making it unsuitable for most traditional reef aquariums.

Quick Care Guide

Care Level: Moderate
Minimum Tank Size: 120 gallons
Temperament: Peaceful
Diet: Omnivore
Reef Safe: No
Region: Indo-Pacific
Scientific Name: Chaetodon ulietensis

Tank Requirements

Provide a mature marine aquarium with substantial rockwork, caves, and sheltered passages along with generous open swimming space. Although relatively modest in adult length, the Double Saddle Butterflyfish is an active cruiser and benefits from a long aquarium with room to move comfortably throughout the display.

Established live rock provides valuable shelter and natural browsing surfaces. Arrange the aquascape so the fish can investigate rockwork without being confined by narrow passages or excessively dense coral structures.

Moderate water movement, good oxygenation, efficient filtration, and stable water quality are recommended. A secure aquarium cover is also advisable, particularly during acclimation when newly introduced butterflyfish may make sudden movements if startled.

Diet and Feeding

The Double Saddle Butterflyfish is an omnivorous reef browser that naturally consumes both plant and animal material, including algae and a variety of small benthic invertebrates. Coral polyps, anemones, worms, and other sessile organisms may also be investigated as food.

In captivity, offer mysis shrimp, enriched brine shrimp, finely chopped shrimp, clam, mussel, krill, and quality frozen marine blends. Butterflyfish preparations containing marine invertebrate ingredients can provide additional variety.

Spirulina-based foods, marine algae preparations, and high-quality omnivore pellets can also be incorporated once the fish is feeding confidently. Feed two to three smaller meals per day when practical.

Temperament and Tankmates

The Double Saddle Butterflyfish is generally peaceful toward unrelated marine fish and works well with many appropriately sized community species. Suitable tankmates include tangs, rabbitfish, peaceful wrasses, clownfish, larger gobies, and compatible angelfish.

Adults naturally occur alone, in pairs, or in small groups. A compatible pair may be maintained in a sufficiently spacious aquarium, although two unrelated specimens should not automatically be expected to pair successfully.

Use caution with other butterflyfish, particularly similar-looking species, as territorial behavior may occur. Avoid highly aggressive tankmates that could intimidate the fish or interfere with feeding.

Reef Compatibility

The Double Saddle Butterflyfish is not considered reef safe. Its natural feeding behavior includes coral polyps and other sessile invertebrates, and captive specimens may nip or consume stony corals, soft corals, mushroom corals, zoanthids, anemones, and tubeworms.

Clam mantles and other exposed fleshy invertebrates may also be investigated. Frequent feeding does not guarantee that a specimen will ignore desirable reef organisms.

A fish-only or fish-only-with-live-rock aquarium is the most dependable long-term environment.

Water Parameters

Temperature: 75–80°F
Specific Gravity: 1.024–1.026
pH: 8.1–8.4
Alkalinity: 8–12 dKH

Stable salinity, good oxygenation, and consistently clean water are more important than attempting to maintain an exact value within these ranges.

Common Considerations

• Not reef safe: Corals, anemones, tubeworms, and other sessile invertebrates may be nipped or consumed.

• Mature aquarium preferred: Established rockwork provides shelter and natural browsing opportunities.

• Varied diet is important: Offer a combination of marine invertebrate foods, frozen preparations, and algae-based foods.

• Butterflyfish compatibility: Use caution when combining it with other butterflyfish, particularly similar species.

• Active swimmer: Despite its moderate adult size, generous horizontal swimming space is important for long-term housing.