The threadfin butterflyfish (Chaetodon auriga), also known as the auriga butterflyfish, is a striking marine fish popular among aquarium enthusiasts. Here are some key details about the threadfin butterflyfish:

Appearance

• Coloration: The threadfin butterflyfish is predominantly white with diagonal black stripes running from the upper body to the lower body. It has a distinct black spot near the tail, which often helps in confusing predators.
• Fins: The dorsal fin has a thread-like extension, giving the fish its name. This filament is particularly long in juveniles.
• Size: Adults typically reach up to 9 inches (23 cm) in length.

Habitat

• Distribution: The threadfin butterflyfish is found in tropical and subtropical waters of the Indo-Pacific region, from the Red Sea and East Africa to Hawaii and the Marquesas Islands.
• Environment: They inhabit coral reefs and lagoons, usually at depths of 1 to 35 meters. They are often found alone or in pairs, sometimes forming small groups.

Behavior and Diet

• Diet: In the wild, threadfin butterflyfish feed on a variety of invertebrates, including coral polyps, small crustaceans, and algae. In captivity, they should be fed a varied diet consisting of high-quality flake or pellet food, frozen or live brine shrimp, mysis shrimp, and specialized foods for butterflyfish.
• Behavior: These fish are generally peaceful and can coexist with other non-aggressive fish. However, they may be territorial towards other butterflyfish.

Aquarium Care

• Tank Size: A minimum tank size of 75 gallons is recommended to accommodate their active swimming behavior and size.
• Water Conditions: They thrive in water with temperatures between 72-78°F (22-26°C), pH levels of 8.1-8.4, and specific gravity of 1.020-1.025.
• Reef Compatibility: While beautiful, threadfin butterflyfish are not entirely reef-safe, as they may nip at coral polyps and other invertebrates. Caution should be exercised when adding them to reef tanks.

Lifespan and Health

• Lifespan: With proper care, threadfin butterflyfish can live up to 10 years in captivity.
• Health: They are relatively hardy but can be susceptible to common marine diseases. Maintaining pristine water quality and a stress-free environment is crucial for their health.

The threadfin butterflyfish is a captivating addition to a marine aquarium, offering both beauty and an interesting presence. However, potential owners should be aware of their specific care requirements and potential impact on reef environments.