Klein’s Butterflyfish (Chaetodon kleinii)

The Klein’s Butterflyfish, also known as the Sunburst Butterflyfish or Black-lipped Butterflyfish, is widely considered the hardiest of all butterflyfishes. While most butterflies are notoriously finicky eaters, the Klein’s is an adaptable omnivore that often thrives where others struggle. It is most famous in the hobby for its role as a "biological control" for nuisance anemones.

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Key Information

• Common Names: Klein’s Butterfly, Sunburst Butterfly, Orange Butterflyfish

• Scientific Name: Chaetodon kleinii

• Origin: Indo-Pacific (Red Sea and East Africa to Hawaii)

• Max Size: 15 cm (approx. 6 inches)

• Lifespan: 7–10 years

• Temperament: Peaceful; may be shy when first introduced

• Diet: Omnivore – Readily accepts frozen, flake, and pellet foods

• Care Level: Easy (for a Butterflyfish)

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Appearance & Identification

The Klein’s Butterfly has a warm, subtle aesthetic:

• Coloration: A base of golden yellow to tan with two broad, faint white vertical bars on the front half of the body.

• The "Black Lip": It features a distinctive black-to-dark-brown snout and a dark vertical bar running through the eye.

• Scale Detail: The scales often have a pearlescent quality, giving the fish a "shimmering" look under reef lights.

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Behaviour & Tank Compatibility

• Aiptasia & Majano Hunter: This is the primary reason many reefers keep this fish. It is one of the most reliable consumers of Aiptasia and Majano anemones.

• Reef Safe (with Significant Caution): This fish is a "risky" reef inhabitant. While it eats nuisance anemones, it may also nip at LPS corals, soft corals (especially Xenia), and leather corals. It is generally safe with most SPS corals and ornamental shrimp.

• Social Structure: Can be kept singly or as a mated pair. It is very peaceful toward other fish but can be territorial toward other butterflyfish of a similar shape.

• Tank Mates: Excellent with Tangs, Wrasses, and Clownfish. Avoid very aggressive "bullies" that might prevent it from feeding.

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Ideal Tank Setup

• Tank Size: A minimum of 200L (55 Gallons) is required. They are active and need space to cruise the rockwork.

• Rockwork: Provide plenty of live rock for the fish to graze on. They naturally pick at algae and small invertebrates throughout the day.

• Water Quality: While hardier than most, they still require stable marine conditions and high oxygenation.

• Feeding: Unlike many of its cousins, it is a "pig" when it comes to food. It will greedily eat frozen mysis, brine shrimp, and even high-quality spirulina flakes.