Radial Filefish

The Radial Filefish (Acreichthys radiatus), also called the Radial Leatherjacket or Radiated Filefish, has pale lines that fan outward from the eye and break into bands and short marks farther back on the body. Small skin flaps soften its outline. Its ground color and contrast can shift with its surroundings, and mature males develop a small patch of bristles on each side of the tail base.

This species occurs on shallow reefs in the tropical Indo-West Pacific. It is often seen among soft corals, where its stripes and slender outline help it blend into the tentacles. Observations of wild fish include feeding on soft coral polyps and tissue. The same habitat can provide both shelter and opportunities for feeding.

In an aquarium, the Radial Filefish does best with quiet cover, fine foods, and tankmates that give it time to feed. It can hover almost motionless beside a rock edge and then move a short distance to inspect food. Plan for its adult needs and its potential to browse corals, even if the fish is small or readily accepts prepared food.

Quick Care Guide

Care Level: Moderate
Minimum Tank Size: 30 gallons
Adult Size: Up to 2.8 inches (7 cm total length)
Temperament: Peaceful
Diet: Omnivore
Reef Safe: No
Region: Tropical Indo-West Pacific
Scientific Name: Acreichthys radiatus

Tank Requirements

Provide at least 30 gallons for one adult up to 2.8 inches (7 cm) in total length. Choose a footprint that leaves open water beside the rockwork so the fish can move between cover and feeding areas. Use a larger aquarium for a compatible pair or a community with several fish that feed around the rocks.

Arrange stable rockwork with shaded ledges and several short routes into cover. Upright structures or established marine macroalgae can provide additional shelter. Leave a clear patch immediately outside the main retreat so the fish can feed close to cover and be observed without disturbing it.

Give the fish a calmer feeding lane. Direct gentle flow past one ledge and maintain stronger circulation elsewhere for oxygenation and waste removal. Check where small particles travel. A filefish that stays low behind the rocks may need food released closer to its shelter.

Use a mature biological filter, a fitted lid, and guards on accessible pump intakes. Keep the main feeding area clear enough to siphon food that settles. New fish may choose a different refuge than expected, so observe where the fish spends time and move its initial feeding station there.

Provide an alternate shelter if other fish claim the first one. Keep the routes between retreats open as rockwork and other structures change. A small fish should be able to reach food without crossing a tankmate’s territory each time it leaves cover.

Diet and Feeding

Offer a varied marine omnivore diet centered on small animal foods, with balanced preparations and some algae-based foods in the rotation. The species has been observed feeding on soft coral tissue in the wild. Aquarium-raised individuals have also accepted frozen mysis and pellets, and feeding response should be checked for the individual fish.

Rotate foods from these options.

• Small frozen mysis shrimp
• Enriched brine shrimp
• Fine frozen copepods or other marine plankton foods
• Finely chopped marine shrimp or clam
• Balanced marine omnivore preparations
• Fine pellets or spirulina-based foods once accepted

Start with two to three small meals daily. Release a few pieces close to the fish’s preferred cover and observe whether it swallows them. In a community, feed quick tankmates at a separate location before offering the filefish its portion.

Use particles it can pick up easily. Its mouth is small, and a fish that repeatedly spits out larger pieces may eat finer foods more readily. Try frozen plankton, small mysis, or enriched live prey when a new fish is slow to begin feeding. Introduce complete prepared foods as it settles.

Observe body condition over several meals. A fish can inspect rockwork throughout the day while taking little prepared food. Check whether it consistently eats from the rotation and remove leftovers before they break down beneath ledges.

Temperament and Tankmates

The Radial Filefish is generally peaceful toward unrelated fish. It tends to hover near cover and makes short trips to feed. Choose calm, appropriately sized tankmates that leave its shelters available and give it time to take food. Large predators and persistent fin nippers are poor matches.

One specimen is a practical choice in a modest display. If keeping compatible individuals together, provide more space, separate retreats, and several feeding positions. Observe each fish at meals, since one can miss food without obvious aggression.

Repeated pursuit, damaged fins, or a fish that rarely emerges to feed signals a need to check the setup. Add a second route into cover or deliver food farther from the busiest part of the aquarium. Separate incompatible fish if normal feeding does not resume.

Reef Compatibility

The Radial Filefish is classified Non Reef Safe for general stocking. It has been observed feeding on soft coral polyps and tissue, and some aquarium-raised fish have also nipped corals. Individual behavior varies, so prepared food acceptance alone is insufficient to judge coral compatibility.

A mature fish-only aquarium with live rock and sheltered structure is the more predictable setup when protecting ornamental corals is a priority. If kept with corals, monitor colonies around its preferred cover for repeated picking and tissue loss. Its natural association with soft corals helps explain its appearance and behavior.

Water Parameters

Temperature: 75–78°F
Specific Gravity: 1.024–1.026
pH: 8.1–8.4
Alkalinity: 8–12 dKH

Use a fully cycled, well-oxygenated marine aquarium with undetectable ammonia and nitrite. Replace evaporated water with fresh water and match replacement saltwater to the aquarium during water changes. Verify that flow reaches sheltered areas after servicing pumps.

Track nutrient levels as feeding increases, and remove fine food that settles beneath ledges. Observe the fish’s normal appetite, breathing, and use of cover during acclimation so changes in condition are easier to spot.

Common Considerations

• Adult Housing: Provide at least 30 gallons for one adult up to 2.8 inches (7 cm), with quiet cover and room to turn.
• Identification: Look for pale lines radiating from the eye. Adult males have bristles at the tail base.
• Feeding Access: Deliver fine foods near shelter and confirm swallowing at several meals.
• Tankmates: Choose calm companions and use separate feeding positions if competition develops.
• Reef Risk: This species can feed on coral polyps and tissue. Protect ornamental corals by keeping them in a separate display.
• Handling: Use a suitable rigid container where practical. The dorsal spine can catch in fine mesh.