Aiptasia Eating Filefish - Acreichthys tomentosus

Medium (2-3")

$69.99

Aiptasia Eating Filefish - Acreichthys tomentosus

Filefish Reef Safe Caution

$69.99

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Diet

Mysis Finely Chopped Seafood Aiptasia

Min Tank Size 75 gallons

Temperament Peaceful

Reef Safe With Caution

Care & Diet Feeding, nutrition, and best practices.

Diet Type: Omnivore

Aiptasia Eating Filefish are omnivorous, with a diet that should include a variety of foods to ensure nutritional balance. While they are known for consuming Aiptasia anemones, they may not rely solely on them. Supplement their diet with high-quality marine flakes, pellets, and frozen foods such as brine shrimp and mysis shrimp. Feeding should occur 2-3 times daily in small amounts to prevent overfeeding and maintain water quality. It's important to monitor their eating habits, as they can be finicky eaters, and adjust the diet as necessary to ensure they receive adequate nutrition.

Mysis Finely Chopped Seafood Aiptasia

Behavior Temperament, activity level, and interactions.

Temperament: Peaceful

Aiptasia Eating Filefish exhibits slow, deliberate swimming patterns, often hovering near coral reefs. Preferring solitude or small groups, it maintains a peaceful demeanor but may exhibit mild territoriality, especially in confined spaces. Generally compatible with other non-aggressive species, it can coexist with a variety of reef inhabitants. However, caution is advised with small crustaceans or ornamental invertebrates due to its natural predation tendencies. This filefish is particularly valued for its ability to control Aiptasia populations within aquariums, making it a beneficial addition for reef enthusiasts.

Tank & Aquascape Tank requirements and aquascaping tips.

Min Tank Size: 75 gallons
Max Size: 5.5 inches
Care Level: Easy
Origin: Indonesia

Compatibility Tank mates, aggression, and introduction order.

Temperament: Peaceful
Reef Safe: With Caution

Filefish Reef Safe With Caution Omnivore Aiptasia Eater

Reef & Health Reef safety, common issues, and prevention.

Reef Safe: With Caution
Care Level: Easy

FAQs Answers to the most common questions.

How can I encourage an Aiptasia Eating Filefish to start eating Aiptasia in my reef tank instead of prepared foods only?

Keep the fish slightly underfed but not starving, and limit rich prepared foods (like mysis and pellets) to small portions once per day. Place rocks with Aiptasia in a smaller acclimation box with the filefish inside the main tank for a few days so it “learns” them as food with minimal distractions. Target-feed small pieces of Aiptasia (scraped off and offered by tweezers) near its snout. Avoid feeding large meaty items that fully satisfy it. Once you see it nipping at Aiptasia consistently, you can release it into the full display and gradually return to a normal, varied diet.

My Aiptasia Eating Filefish cleared the Aiptasia and is now nipping at Zoas and LPS. Is there any way to stop the coral nipping behavior without removing the fish?

Increase feeding frequency with smaller, varied meals (mysis, brine, finely chopped clam, quality pellets, and algae-based foods) so it’s less motivated to graze on corals. Add alternative “graze targets” such as small pieces of clam or mussel on a rock, or dried nori clipped near its favorite area. Re-arrange or temporarily move the most targeted corals to break its routine. Sometimes moving the filefish to a different part of the tank in an acclimation box for a week resets habits. However, some individuals remain persistent coral nippers; if targeted corals are expensive or show continuous damage (recession, closed polyps for many days), the only reliable solution may be to rehome the fish or move it to a soft-coral or FOWLR setup.

How can I reliably sex Aiptasia Eating Filefish and what are the signs of a compatible pair versus two males fighting?

Males often show more orange or yellow spotting around the dorsal area and may develop a slightly more pronounced dorsal filament, but visual sexing is not always reliable. Behavior is a better guide: a compatible pair will often swim within sight of each other, display parallel swimming, and occasionally “hover” together near rockwork without extended chasing. Two males often engage in repeated short chases, flaring dorsal and anal fins, and facing off head-to-head with stiff body posture, sometimes with nipping at fins. In small tanks (under ~40 gallons), two males are more likely to fight, while a true pair usually settles into a loose bond with occasional mild displays but no persistent aggression.

What specific acclimation and quarantine steps help Aiptasia Eating Filefish transition from wild capture to reef-safe conditions and reduce the chance of disease?

Quarantine for at least 2–4 weeks in a bare-bottom or simple QT tank with plenty of PVC hideouts and a few small rocks seeded with Aiptasia. Start with drip acclimation, then keep salinity stable around 1.025 and temperature 24–26°C (75–79°F). Offer live or frozen foods that move in the current (mysis, enriched brine) and bits of Aiptasia on small rocks to trigger feeding. Observe for external parasites (spots, scratching, frayed fins) and internal issues (stringy white feces, bloating, refusal to eat). If needed, treat in QT with appropriate meds (e.g., praziquantel for internal worms, a copper or alternative protocol for ich/velvet, following product guidelines). Do not use copper in the display tank. Once eating multiple foods, showing no symptoms, and maintaining weight, transfer gently to the main tank with the lights dimmed to reduce stress.

In what tank sizes and social setups do Aiptasia Eating Filefish show the most natural behavior without becoming overly shy or aggressive?

For a single specimen, 30 gallons is an absolute minimum; 40+ gallons with moderate rockwork and multiple caves works better. This species often feels more secure with visual barriers, so avoid overly open aquascapes. They typically do well in peaceful community tanks with small to medium non-aggressive fish (clowns, gobies, fairy wrasses, chromis). Avoid large, boisterous tankmates (big triggers, aggressive tangs, large wrasses) that may intimidate them, causing constant hiding and poor feeding. If keeping a pair, aim for 55+ gallons with ample rock and at least two distinct “zones” so they can separate. Provide moderate flow and mid-level lighting; they’ll spend time picking at rock, occasionally hovering in midwater. A secure environment with low aggression helps them remain visible and active, making their Aiptasia-grazing behavior more reliable.

Goes well with:

You will receive a fish SIMILAR in design and size to the fish in the photo. This is NOT a WYSIWYG fish.

Aiptasia Eating Filefish – Acreichthys tomentosus

The Aiptasia Eating Filefish, also known as the Matted Filefish or Bristle-tail Filefish, is a distinctive saltwater fish with an angular body, an elongated snout, and mottled green, tan, brown, and cream coloration. Irregular markings and small skin flaps help break up its outline, allowing it to blend naturally into rockwork, seagrass, and branching reef structures. Its slow, deliberate swimming style and constantly changing camouflage give this marine aquarium fish a unique appeal beyond its reputation for pest control.

Native to the Indo-West Pacific, Acreichthys tomentosus ranges from Sri Lanka through Indonesia to New Caledonia and north to southern Japan. It inhabits shallow reefs, seagrass beds, rubble zones, and other protected coastal environments. Adults can reach approximately 5.5 inches and naturally feed on amphipods, polychaete worms, mollusks, and other small invertebrates.

This peaceful filefish is widely selected for its tendency to consume nuisance Aiptasia anemones. However, Aiptasia control varies between individuals and should never be guaranteed. Some specimens begin feeding on pest anemones quickly, while others require time or may ignore them entirely. Because it may also nip corals and ornamental invertebrates, it is best described as reef safe with caution.

Quick Care Guide

Care Level: Moderate
Minimum Tank Size: 75 gallons
Temperament: Peaceful
Diet: Omnivore
Reef Safe: With Caution
Region: Indo-West Pacific
Scientific Name: Acreichthys tomentosus

Tank Requirements

Provide a mature saltwater aquarium with abundant live rock, sheltered caves, branching structures, and several quiet areas where the filefish can rest or retreat. Keep part of the aquarium open for swimming, but avoid creating an overly exposed aquascape. This naturally solitary species is commonly associated with shallow reefs, rubble, vegetation, and seagrass habitat where camouflage and nearby cover are important.

Moderate, well-distributed water movement is appropriate. Include lower-flow areas around the rockwork because this filefish is not a powerful open-water swimmer. Strong filtration and stable water quality are important, especially when the fish is being fed several small meals each day.

No specialized substrate is required, although sand or fine gravel complements a natural reef-style setup. Use a fitted lid or secure mesh cover because a startled specimen may jump. Avoid placing it in an aquarium dominated by aggressive fish or intense feeding competition, particularly during its initial acclimation period.

Diet and Feeding

Although best known for eating Aiptasia, this filefish requires a complete and varied diet. In the wild, important prey includes amphipods, polychaete worms, and mollusks. Aiptasia should be viewed as a potential supplemental food source rather than the foundation of its long-term captive diet.

Offer mysis shrimp, enriched brine shrimp, finely chopped clam or mussel, chopped shrimp, squid, scallop, frozen marine blends, and quality omnivore pellets. Spirulina-enriched foods and frozen preparations containing marine algae can provide additional dietary variety. Soft food pressed into rock crevices may encourage the fish’s natural picking behavior.

Feed small portions two to three times daily. Newly introduced individuals may be hesitant feeders and should be observed carefully to confirm that they are receiving enough food. Continue regular feeding even after the Aiptasia population declines; the fish cannot be expected to survive solely on occasional pest anemones.

Temperament and Tankmates

The Aiptasia Eating Filefish is generally peaceful, somewhat shy, and compatible with many community marine fish. Suitable tankmates include clownfish, gobies, cardinalfish, blennies, peaceful wrasses, firefish, and other species that will not harass it or monopolize food.

Keep one specimen in most aquariums. It may become territorial toward other filefish, especially members of the same genus or similarly shaped species. A compatible pair should only be attempted in a larger aquarium with plentiful cover and enough room for both fish to establish separate resting areas.

Avoid highly aggressive triggers, large dottybacks, predatory groupers, and exceptionally territorial angelfish. Persistent fin nipping or feeding competition can cause a reserved filefish to remain hidden and lose body condition.

Reef Compatibility

The Aiptasia Eating Filefish is reef safe with caution. Many specimens are maintained successfully in mixed reef aquariums, but individual behavior is unpredictable. The same feeding response that may lead it to consume Aiptasia can also be directed toward desirable sessile invertebrates.

Possible targets include soft corals, fleshy large-polyp stony corals, small-polyp stony corals, zoanthids, anemones, clam mantles, feather duster worms, and other exposed invertebrates. Small ornamental shrimp and crustaceans may also be investigated. Careful observation is essential, particularly after the available Aiptasia has been reduced.

Keeping the fish well fed may reduce unwanted nipping, but it does not eliminate the risk. Aquarists with valuable or delicate corals should have a practical removal plan available before introducing this species.

Water Parameters

Temperature: 75–80°F
Specific Gravity: 1.024–1.026
pH: 8.1–8.4
Alkalinity: 8–12 dKH

Maintain consistent salinity, good oxygenation, and low levels of accumulated waste. Stable conditions are more important than repeatedly adjusting the aquarium to reach one exact reading.

Common Considerations

Aiptasia consumption is not guaranteed: Individual feeding preferences vary, and a separate pest-management plan may still be necessary.
Monitor corals and invertebrates: Soft corals, stony corals, clam mantles, tubeworms, and small ornamental crustaceans may be nipped.
Provide frequent varied meals: Continue feeding two to three times daily after the Aiptasia population declines.
Allow a quiet acclimation period: Shy specimens may hide or feed poorly when housed with aggressive, fast-feeding fish.
Use caution with other filefish: Territorial behavior is most likely toward the same species and similarly shaped relatives.