Clarkii Clownfish (Amphiprion clarkii)
The Clarkii Clownfish, also known as the Yellowtail Clownfish or Clark's Anemonefish, is one of the most widely distributed and hardy species of clownfish in the ocean. It is famous for its adaptability, as it is one of the few clownfish that will naturally host in almost any species of sea anemone. While it is a staple in the hobby, it is significantly larger and more boisterous than the common Ocellaris (Nemo) clownfish.
Key Information
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Common Names: Clarkii Clownfish, Yellowtail Clownfish, Banded Clownfish
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Scientific Name: Amphiprion clarkii
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Origin: Indo-Pacific (Persian Gulf to Western Australia and Japan)
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Max Size: 13–15 cm (approx. 5.5–6 inches) — a large, robust clownfish.
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Lifespan: 10–20+ years
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Temperament: Semi-aggressive; can be very territorial, especially when hosting
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Diet: Omnivore – Accepts almost all aquarium foods
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Care Level: Very Easy
Appearance & Identification
The Clarkii is known for its high-contrast, "sturdy" look:
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The Stripes: Features three bold white vertical bands. The second band is typically wider than on other clownfish and often slants slightly toward the rear.
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Color Variation: Their base color can range from bright orange to jet black, depending on their geographical origin and the type of anemone they host.
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Yellow Tail: Most specimens have a bright yellow-to-white tail, which remains a primary identification feature even in darker individuals.
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Face: They often have a yellow or orange snout, regardless of how dark their body becomes.
Behaviour & Tank Compatibility
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The "Universal Hoster": In the wild, Clarkii clownfish are known to host in all 10 species of symbiotic anemones. If you have an anemone that other clowns are ignoring (like a Long Tentacle or Saddle Anemone), a Clarkii is the most likely candidate to move in.
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Aggression: They are significantly more aggressive than Percula or Ocellaris clowns. As they mature, they will fiercely defend their anemone or favorite corner of the tank, sometimes even "attacking" the hand of their owner during maintenance.
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Social Structure: Best kept as a mated pair. They follow a strict hierarchy where the female is the largest and most dominant.
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Tank Mates: Best housed with active, robust fish like Tangs, larger Wrasses, and Damselfish. Avoid very shy or tiny tank mates in smaller systems, as the Clarkii may bully them.
Ideal Tank Setup
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Tank Size: Due to their large adult size and active nature, a minimum of 115L (30 Gallons) is required for a pair. 200L+ is recommended if you plan to keep them with other fish.
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Anemone Choice: While they do not need an anemone to survive, they thrive with one. Popular choices include the Bubble Tip (Entacmaea quadricolor) or Carpet Anemones.
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Rockwork: Provide plenty of live rock with caves. If they don't have an anemone, they will often "host" in a specific cave or even a patch of large-polyp stony (LPS) coral like Torch or Frogspawn.
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Lid: Like most reef fish, they can jump if startled or during a chase. A secure lid is highly recommended.
Why Choose the Clarkii Clownfish?
The Clarkii is the "muscle" of the clownfish world. It is a fantastic choice for a large community reef or for hobbyists who want a clownfish that is active and visible. Their legendary hardiness makes them nearly bulletproof, and their willingness to host almost any anemone makes them a reliable choice for creating that iconic "symbiotic" display.
