Blackbar Filefish

The Blackbar Filefish (Pervagor janthinosoma), also called the Ear-spot Filefish or Gillblotch Leatherjacket, has a dark blue to black blotch around the gill opening, just ahead of the pectoral fin. Fine dark lines mark the sides, and the tail ranges from orange to red. Color can vary considerably, so the dark gill blotch is a better identification feature than tail color alone. This is a separate species from the Redtail Filefish (Pervagor melanocephalus).

This filefish occurs across the Indo-Pacific, from East Africa to the western and central Pacific, north to southern Japan and south to Australia. It inhabits shallow lagoons and coral-rich seaward reefs, where it is often found close to rocks, sponges, and crevices at the bases of large coral colonies. It can slip into cover quickly when disturbed. Adults may occur in pairs in the wild, and one fish may remain concealed while the other is visible.

In the aquarium, the Blackbar Filefish does best with calm tankmates and a sheltered place to feed. It moves between rock cover and short stretches of open water, inspecting surfaces and taking small bites. A mature fish-only aquarium with live rock provides the cover and feeding access it needs while keeping vulnerable ornamental invertebrates out of its browsing area.

Quick Care Guide

Care Level: Moderate
Minimum Tank Size: 50 gallons
Adult Size: Up to 5.5 inches (14 cm total length)
Temperament: Peaceful
Diet: Omnivore
Reef Safe: No
Region: Indo-Pacific
Scientific Name: Pervagor janthinosoma

Tank Requirements

Provide at least 50 gallons for long-term adult housing, including when starting with a smaller fish. Adults reach about 5.5 inches (14 cm) in total length. Choose a footprint with enough front-to-back room for the fish to turn beside the rocks and clear routes between retreats. Allow additional room if keeping several community fish that use the same feeding area.

Arrange stable rockwork with shaded ledges, caves, and crevices at different heights. Leave open water directly outside the shelters so the filefish can emerge, browse, and take passing food. Several openings let it withdraw from a tankmate without having to abandon its usual feeding area.

Keep one feeding area out of direct pump flow. A gentle current past a ledge helps bring fine food within reach. Position stronger flow elsewhere to keep the aquarium oxygenated and move debris toward filtration. Check that a sheltered corner still gets enough water movement for uneaten food to remain visible and accessible.

Use an established biological filter, good surface movement, and a secure cover around cables and plumbing. Make it easy to siphon around rock bases and remove food that settles below overhangs. In the first days after introduction, observe which shelter the fish actually uses and deliver food where it can reach it.

Diet and Feeding

Feed a varied omnivore diet with an emphasis on small marine animal foods. Benthic invertebrates are part of its natural feeding ecology. Offer finely cut seafood and a balanced prepared food, with algae-based items as part of the rotation. Choose pieces that the fish can pick up and swallow without repeatedly dropping them.

Rotate suitable foods such as the following.

• Frozen mysis shrimp
• Enriched brine shrimp
• Finely chopped marine shrimp, clam, or other seafood
• Balanced frozen marine omnivore preparations
• Finely sized algae-based marine foods

Start with two to three small meals per day. Deliver some food beside its shelter and watch for swallowing before offering more. In a mixed aquarium, feed faster fish in one part of the tank, then release a small portion near the filefish’s retreat so it has time to inspect and take the food.

Check feeding during acclimation. A Blackbar Filefish may stay close to cover at first or ignore unfamiliar prepared food. Try small frozen foods, or enriched live prey if needed to start a feeding response. Introduce other foods once it is taking meals reliably and use body condition and appetite to guide portions.

Remove uneaten food before it breaks down, particularly pieces that settle behind ledges. Track whether the filefish stays at a healthy weight over several feedings. If it repeatedly approaches food without swallowing, try smaller pieces and a quieter feeding position before increasing the amount.

Temperament and Tankmates

The Blackbar Filefish is generally peaceful toward unrelated tankmates. It can be secretive in a busy aquarium and may spend more time under a ledge if other fish crowd its feeding area. Choose calm companions that allow it to make repeated feeding trips near cover.

One filefish is the simplest arrangement in a typical display. Wild pairs do occur, but pairing unfamiliar fish in an aquarium requires extra space and close observation. Provide separate retreats and feeding stations if keeping similar fish together, and have a way to separate them if one controls both areas.

Avoid persistent fin nippers and fish that rush every portion of food. Watch for a filefish that repeatedly retreats before taking a bite, remains hidden through several meals, or develops damaged fins. Separate feeding areas or a change in tankmates may be needed to restore regular feeding.

Reef Compatibility

The Blackbar Filefish is classified Non Reef Safe. It browses on reef surfaces and can pick at exposed ornamental invertebrates. Its association with coral-rich habitat describes where it lives and shelters. It does not establish compatibility with a mixed reef display.

Avoid keeping it with valuable coral colonies, ornamental tubeworms, or other vulnerable sessile invertebrates. Feeding it regularly supports good condition, but does not prevent browsing. A fish-only system with live rock lets the fish use natural cover and feeding surfaces while reducing conflicts with ornamental livestock.

Water Parameters

Temperature: 74–78°F
Specific Gravity: 1.024–1.026
pH: 8.1–8.4
Alkalinity: 8–12 dKH

Keep the aquarium fully cycled with undetectable ammonia and nitrite. Maintain steady specific gravity through freshwater top-off and match the temperature and salinity of new saltwater during water changes. Check circulation and surface movement after servicing pumps or filters.

Use nutrient tests and the amount of uneaten food to guide maintenance. The fish benefits from multiple small meals, so clean mechanical filtration and siphon accessible scraps as needed. Changes in appetite, breathing, or shelter use are reasons to check water quality and watch for competition around the retreat.

Common Considerations

• Adult Housing: Provide at least 50 gallons with covered retreats, sheltered flow, and room to turn beside the rockwork.
• Species Identification: Look for the dark blotch around the gill opening. The orange-red tail can also occur in other filefish.
• Feeding Access: Offer small pieces near cover and confirm swallowing before adding more food.
• Tankmates: Choose calm fish that give the filefish time to feed and access to more than one retreat.
• Reef Compatibility: House in a fish-only aquarium with live rock. Browsing can put exposed ornamental invertebrates at risk.
• Handling: Use a suitable rigid container when practical. The first dorsal spine can snag in fine mesh.