Auriga Butterflyfish

The Auriga Butterflyfish, Chaetodon auriga, also known as the Threadfin Butterflyfish, is a beautifully patterned saltwater fish distinguished by its bright white body, intersecting dark chevron markings, yellow posterior coloration, and bold black band running through the eye. Most populations display a prominent black eyespot near the rear of the dorsal fin, while mature specimens develop the elegant thread-like dorsal extension responsible for the Threadfin common name.

Native to an exceptionally broad Indo-Pacific range extending from the Red Sea and East Africa to Hawaii and French Polynesia, this species inhabits coral reefs, lagoons, rubble zones, and other structured marine habitats. It may occur singly, in pairs, or in loose groups while roaming the reef in search of small invertebrates, coral polyps, algae, and other foods.

Reaching approximately 10 inches as an adult, the Auriga Butterflyfish is an active and eye-catching marine aquarium fish best suited to a spacious fish-only or fish-only-with-live-rock aquarium. It is generally adaptable for a butterflyfish once established and feeding well, but its natural feeding behavior makes it an unsuitable choice for most reef aquariums containing valuable corals and sessile invertebrates.

Quick Care Guide

Care Level: Moderate
Minimum Tank Size: 125 gallons
Temperament: Peaceful
Diet: Omnivore
Reef Safe: No
Region: Indo-Pacific – Red Sea and East Africa to Hawaii and French Polynesia
Scientific Name: Chaetodon auriga

Tank Requirements

Provide a spacious, established marine aquarium with a combination of open swimming room and substantial rockwork. Caves, overhangs, and sheltered passages allow the fish to retreat when desired, while broad open areas accommodate the continuous cruising behavior typical of adult butterflyfish.

Because this species can reach approximately 10 inches, horizontal swimming space is important. Avoid creating an overly dense aquascape that restricts movement, particularly as the fish reaches adult size.

Moderate water movement, strong oxygenation, efficient filtration, and consistently stable water quality are recommended. Mature live rock can provide additional browsing opportunities and may help newly introduced specimens settle into the aquarium.

A secure lid is advisable, especially during acclimation when a startled butterflyfish may make sudden movements toward the surface.

Diet and Feeding

The Auriga Butterflyfish is an omnivore with a broad natural diet that includes polychaete worms, sea anemones, coral polyps, algae, and other small reef-associated foods.

In captivity, offer a varied selection of mysis shrimp, enriched brine shrimp, finely chopped shrimp, clam, mussel, squid, and quality frozen marine blends. Specialized butterflyfish preparations containing marine invertebrate material can provide additional dietary variety.

Spirulina-based foods, marine algae preparations, and high-quality omnivore pellets can also be included. Newly introduced specimens that are reluctant to eat may respond particularly well to clam or mussel presented on the shell, frozen mysis, or foods placed close to familiar rockwork.

Feed two to three smaller meals per day when practical to maintain good body condition.

Temperament and Tankmates

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

Territorial behavior may occur toward other butterflyfish, especially similar-looking species or additional Auriga Butterflyfish. A single specimen is the most straightforward option for most aquariums.

Adults naturally occur singly, in pairs, and occasionally in aggregations. Compatible established pairs may be maintained in sufficiently spacious systems, but two randomly selected individuals should not be assumed to form a peaceful pair.

Avoid excessively aggressive tankmates that may continually harass the butterflyfish or prevent it from feeding.

Reef Compatibility

The Auriga Butterflyfish is not considered reef safe. Coral polyps form part of its natural diet, and specimens may actively nip at or consume both stony and soft corals.

Sea anemones, feather duster worms, and other sessile invertebrates may also be investigated or eaten. Individual feeding preferences can vary, but the risk to desirable reef organisms is significant enough that this species should not be recommended for a traditional coral reef aquarium.

A fish-only or fish-only-with-live-rock system provides the most predictable 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, excellent oxygenation, and consistently good water quality are more important than maintaining an exact value within these ranges.

Common Considerations

• Not reef safe: Coral polyps and several types of sessile invertebrates may be consumed or repeatedly nipped.

• Large adult butterflyfish: Adults can approach 10 inches and require substantial open swimming room.

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

• Butterflyfish compatibility: Territorial behavior may occur toward other butterflyfish, particularly similar species.

• Acclimation: Newly introduced specimens may initially be cautious and benefit from abundant shelter and highly palatable marine foods.