Orangetail Blue Damselfish (Chrysiptera cyanea)

Orangetail Blue Damselfish (Chrysiptera cyanea)

The Orangetail Blue Damselfish, often simply called the Blue Devil, is the "electric blue" pulse of the Indo-Pacific reefs. While you might recognize the name from the Orange Line Damsel we discussed earlier, the "Orangetail" specifically refers to the sexually dimorphic males of this species. It is a fish of extremes: extreme color, extreme hardiness, and an extremely bold personality that belies its small size.

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Key Information

• Common Names: Orangetail Blue Damsel, Blue Devil, Cornflower Damsel

• Scientific Name: Chrysiptera cyanea

• Origin: Indo-West Pacific (Indonesia to the Great Barrier Reef)

• Max Size: 8 cm (approx. 3 inches)

• Lifespan: 5–10 years

• Temperament: Aggressive; highly territorial

• Diet: Omnivore – Opportunistic feeder

• Care Level: Very Easy

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Appearance & Identification

The C. cyanea is famous for its "high-definition" color:

• The Electric Blue: The entire body is a brilliant, almost glowing neon sapphire blue. Under high-quality reef lighting, it looks like it is powered by LEDs.

• The "Orangetail" (The Male): In this species, the males develop a bright orange-to-yellow tail fin and often an orange-tinted snout.

• The Female: Generally solid blue with a small black spot at the base of the rear dorsal fin.

• The Eyes: Features a dark horizontal bar through the eye, giving it a look of constant "predatory" focus.

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Behaviour: The "Reef Guardian"

• Fearless Territory: This fish is the "security guard" of the rockwork. It will select a specific territory and aggressively drive away any fish—even those five times its size—that gets too close.

• The "Blue Flash": They are incredibly fast. You will often see them "flashing" across the tank to chase a rival or grab a piece of food.

• Reef Safe: 100% Reef Safe with corals and clams. However, they may harass very small, delicate shrimp or sessile invertebrates if they are in their "territory."

• Social Structure: Only keep one male per tank unless the aquarium is very large (over 400L). You can keep a male with a group of females if they are all added at the same time.

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Ideal Tank Setup

• Tank Size: A minimum of 75L–115L (20–30 Gallons) for a single specimen. In larger tanks, their aggression is diluted because other fish have room to escape.

• Rockwork: Provide complex rock structures with multiple exits. This allows the Damsel to feel secure in its "fortress" while giving other fish places to hide.

• Feeding: They are among the easiest fish to feed. They will thrive on a mix of frozen mysis, brine shrimp, high-quality flakes, and herbivore pellets.

• Water Quality: This is a "bulletproof" fish. It can handle fluctuations in water quality that would be fatal to delicate wrasses, making it a great choice for maturing a system.

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Why Choose the Orangetail Blue Damsel?

The Orangetail Blue Damsel is for the hobbyist who wants vibrant, moving color that never fades. While they have a reputation for being "mean," their aggression is actually just high activity and confidence. If you stock them correctly with other assertive fish (like Tangs or Dottybacks), they are a joy to watch.