Orange Tailed Filefish (Pervagor Janthinosoma)

Orange-Tailed Filefish (Pervagor janthinosoma)

The Orange-Tailed Filefish, also known as the Earspot Filefish or Blackbar Filefish, is a colorful and secretive member of the Monacanthidae family. Widely distributed across the Indo-Pacific—and very common in Indonesian reef flats—it is a smaller, more vibrant alternative to the larger filefish species. Unlike the Aiptasia-eating filefish, this species is kept primarily for its stunning geometric patterns and inquisitive personality.

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Key Information

• Common Names: Orange-Tailed Filefish, Earspot Filefish, Gill-spot Filefish

• Scientific Name: Pervagor janthinosoma

• Origin: Indo-Pacific (East Africa to the Line Islands, common in Indonesia)

• Max Size: 12–14 cm (approx. 5 inches)

• Lifespan: 5–7 years

• Temperament: Peaceful to Shy; can be secretive

• Diet: Omnivore – Picks at rocks and small invertebrates

• Care Level: Moderate (due to feeding habits)

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Appearance & Identification

This is one of the most intricately patterned filefish in the trade:

• The Tail: Its most striking feature is a bright orange-to-red caudal fin (tail) that contrasts sharply with its body.

• The Body: Features a complex "honeycomb" or reticulated pattern of dark brown, green, and blue-grey.

• The Earspot: Look for a distinct dark blue or black spot located just behind the gill opening, giving it the name "Earspot Filefish."

• The Texture: Like all filefish, its skin has a sandpaper-like texture and it possesses a prominent dorsal spine that it can lock into an upright position to wedge itself into rocks.

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Behaviour & Tank Compatibility

• The "Reef Hermit": This fish is naturally shy and prefers to stay close to the rockwork. It spends its day "poking" its snout into crevices looking for tiny crustaceans, worms, and sponges.

• Reef Safe (with Caution): This is the biggest "catch" with Pervagor species. They are not 100% reef safe. While they generally ignore most corals, they may nip at LPS corals, Zoanthids, and especially the polyps of SPS corals. They are best suited for a "Fish Only With Live Rock" (FOWLR) tank or a very large reef where their nipping is spread out.

• Social Structure: Best kept singly. They can be territorial toward other filefish or similarly shaped species.

• Tank Mates: Excellent with peaceful companions like Anthias, Cardinalfish, and Blennies. Avoid keeping them with aggressive, fast-moving fish that might outcompete them for food.

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Ideal Tank Setup

• Tank Size: A minimum of 115L (30 Gallons).

• Rockwork: Provide extensive live rock with many hiding places. They need to feel they can disappear into the shadows at a moment's notice.

• Water Flow: They prefer low to moderate flow. Because of their body shape, they are not the strongest swimmers in high-current environments.

• Lighting: They appreciate slightly dimmer lighting or plenty of shaded overhangs, as they are naturally found in secretive reef areas.

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Dietary Needs

They are constant foragers and need variety:

• Diet: Offer a mix of frozen mysis, enriched brine shrimp, and chopped seafood (clams or squid).

• Grazing: They appreciate algae-based foods (Nori or spirulina flakes) and will spend a lot of time picking at the "biofilm" on your rocks.

• Feeding Frequency: Feed 2–3 times daily. Because they are slow, deliberate eaters, make sure faster fish don't steal all the food before they can get to it.

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Why Choose the Orange-Tailed Filefish?

The Orange-Tailed Filefish is for the hobbyist who enjoys observing natural behaviors. It is not a "background" fish; it is an intelligent, curious creature that interacts deeply with its environment. While its tendency to nip at corals makes it a risk for some, its stunning orange tail and unique "locking spine" make it a fascinating centerpiece for an Indonesian-themed aquarium with hardy inhabitants.