Description

Threadfin Butterflyfish (Chaetodon auriga)

The Threadfin Butterflyfish is a striking marine species celebrated for its elegant body shape, bold patterning, and distinctive trailing dorsal filament. With its pearly white body, diagonal black lines, golden highlights, and eye-catching false eyespot near the rear dorsal fin, this butterflyfish becomes an instant focal point in larger marine aquariums. Graceful yet active, it brings movement and sophistication to reef and fish-only systems alike.

Native to the Indo-Pacific, Threadfin Butterflyfish inhabit coral-rich lagoons and outer reef slopes. In the wild, they feed on coral polyps, small invertebrates, and algae. In captivity, they adapt well to prepared foods when properly acclimated, but they do require stable water quality and adequate swimming space.

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🐠 Why You’ll Love the Threadfin Butterflyfish

• 🎨 Bold black diagonal lines with golden accents

• 🧵 Signature trailing dorsal “threadfin” extension

• 👀 False eyespot for added visual appeal

• 🌊 Active open-water swimmer for larger tanks

• ✨ Showpiece marine fish for established systems

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🌊 Appearance & Behaviour

Threadfin Butterflyfish grow to approximately 20–23 cm, making them a medium-to-large butterflyfish species. Their tall, laterally compressed bodies allow them to glide effortlessly through open water and weave around rockwork. The long filament extending from the dorsal fin gives them their common name and adds graceful movement as they swim.

They are generally peaceful but may show territorial behaviour toward other butterflyfish or similarly shaped species. Best kept singly or as a bonded pair in spacious systems, they do well with other non-aggressive marine fish.

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🏡 Tank Requirements & Care

Threadfin Butterflyfish require a well-established marine aquarium with excellent water quality and stable parameters.

Tank Size:

• Minimum 350 litres recommended

• Larger systems preferred for long-term success

Water Parameters:

• 🌡 Temperature: 24–27°C

• 💧 pH: 8.1–8.4

• 🌊 Salinity: 1.023–1.025

• Strong, stable filtration and protein skimming essential

Provide ample live rock for grazing and shelter, along with open swimming space.

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🍽 Feeding

In the wild, they feed on coral polyps and small invertebrates, which means reef compatibility can be limited.

In captivity, offer:

• High-quality marine pellets or flakes

• Frozen mysis shrimp

• Brine shrimp enriched with vitamins

• Finely chopped seafood

• Sponge-based butterflyfish preparations

Frequent small feedings help maintain health and reduce coral-nipping behaviour.

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🪸 Reef Compatibility

⚠️ Use caution in reef tanks.

Threadfin Butterflyfish may nip at:

• LPS corals

• Soft corals

• Zoanthids

• Feather dusters

They are generally safer in fish-only with live rock (FOWLR) systems.

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📌 Quick Facts

• Common Name: Threadfin Butterflyfish

• Scientific Name: Chaetodon auriga

• Adult Size: 20–23 cm

• Temperament: Semi-peaceful

• Care Level: Moderate

• Diet: Carnivore / Omnivore

• Reef Safe: With caution

• Water Type: Marine (Saltwater)

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✨ The Threadfin Butterflyfish is a stunning centrepiece species for larger marine aquariums. With proper care, stable water conditions, and thoughtful tank planning, it becomes a graceful and captivating addition to your saltwater display.

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