QUICK STATS

Care Level: Moderate
Diet: Omnivore
Temperament: Peaceful to Semi-Aggressive
Reef-Safe: With Caution
Source: See Options
Approximate Purchase Size: 1.5-3"
Approximate Max Size: 3.5-4"
Recommended Tank Size: 30 Gallons or Larger

AIPTASIA-EATING FILEFISH

The Aiptasia-Eating Filefish (Acreichthys tomentosus) is a unique and useful saltwater fish best known for its ability to help control unwanted aiptasia anemones in reef aquariums. Its mottled tan, green, and brown coloration allows it to blend into rockwork and macroalgae, which makes it look less like a showpiece fish and more like a tiny aquatic goblin assigned to pest control.

This species is popular with reef keepers because it may eat aiptasia, including small anemones tucked into rockwork where manual removal can be difficult. However, like most living “solutions” in reef keeping, results can vary. Some individuals go after aiptasia quickly, some take time, and some look at it like you personally offended them by suggesting they get a job.

Aiptasia-Eating Filefish are generally peaceful and do well in established aquariums with plenty of rockwork, hiding places, and stable water quality. They can be kept in reef tanks, but they are considered reef-safe with caution because some individuals may nip at soft corals, zoanthids, LPS, SPS polyps, clam mantles, or ornamental invertebrates.

Note: Image is a representation of what to expect. The fish you receive may vary slightly in size, color, pattern, and overall appearance.

AQUARIUM REQUIREMENTS

AQUARIUM SIZE

A minimum tank size of 30 gallons or larger is recommended for an Aiptasia-Eating Filefish. Although they stay relatively small, they benefit from a stable, established aquarium with plenty of rockwork to explore and graze around.

Larger aquariums are especially helpful if the filefish is being used for aiptasia control, since more rockwork gives it more natural foraging opportunities and helps reduce stress.

HABITAT RECOMMENDATIONS

Aiptasia-Eating Filefish do best in mature aquariums with plenty of hiding spaces and low-stress tank mates.

Aquascaping: Provide live rock, caves, crevices, and shaded areas. This gives the fish security and allows it to naturally hunt around the aquascape.

Substrate: Sand or fine aragonite works well and helps create a natural reef-style environment.

Rockwork: Established live rock is highly recommended. These fish spend much of their time inspecting surfaces, picking at small foods, and searching for pests.

Tank Cover: A tight-fitting lid is recommended. They are not the most dramatic jumpers in the hobby, but fish remain committed to finding creative ways to become floor jerky.

WATER PARAMETERS

Aiptasia-Eating Filefish are generally hardy once established, but they still require clean and stable saltwater conditions. Pest control fish are still fish, not tiny maintenance equipment with fins. Annoying, but true.

Temperature: 72-78°F
pH Level: 8.1-8.4
Salinity: 1.020-1.026 specific gravity
Alkalinity: 8-12 dKH
Ammonia, Nitrite, and Nitrate: Ammonia and nitrite should remain undetectable. Nitrate should be kept as low as reasonably possible, ideally below 20 ppm.
Water Flow: Low to moderate flow is ideal. They are not powerful swimmers, so avoid excessive direct flow that may make feeding or resting difficult.

DIET

Aiptasia-Eating Filefish are omnivores and should be offered a varied diet of meaty and plant-based marine foods. While they are known for eating aiptasia, they should not be expected to survive on pest anemones alone. That would be convenient, so naturally reef keeping refuses to allow it.

PRIMARY DIET

Pest Control: Many individuals will eat aiptasia anemones, making them a popular natural control option for reef aquariums.

Frozen Food: Offer mysis shrimp, enriched brine shrimp, finely chopped clam, marine blends, and other small frozen foods.

Shop Favorite: Our favorite food to offer is Reef Frenzy by LRS because it provides a strong variety of marine ingredients and usually gets a great feeding response from picky or newly introduced fish.

Prepared Foods: High-quality marine pellets or flakes can be offered once the fish is eating reliably. Smaller pellet sizes are best.

Algae-Based Foods: Spirulina, herbivore blends, and other mixed omnivore foods can be included occasionally for variety.

FEEDING FREQUENCY

Feed small amounts 1-2 times per day once the filefish is eating prepared foods. If the fish is being added for aiptasia control, make sure it is still accepting regular foods so it remains healthy after the aiptasia population decreases.

COMPATIBILITY

Aiptasia-Eating Filefish are usually peaceful and can be kept with many community saltwater fish. They should not be housed with aggressive tank mates that may harass them, outcompete them for food, or bully them into hiding.

COMMON TANK MATES

Fish: Clownfish, cardinalfish, gobies, blennies, peaceful wrasses, firefish, dwarf angelfish, tangs in larger aquariums, and other peaceful to semi-peaceful community fish.

Avoid: Aggressive triggers, large puffers, large wrasses, aggressive damsels, groupers, lionfish, or any fish likely to harass or eat them.

Invertebrates: Use caution. Many individuals ignore common cleanup crew members like snails and hermit crabs, but behavior can vary with small ornamental shrimp or delicate invertebrates.

Coral: Aiptasia-Eating Filefish are reef-safe with caution. They may nip at zoanthids, soft corals, LPS, SPS polyps, clam mantles, or other sessile invertebrates. Some individuals behave perfectly in reef tanks. Others discover your favorite coral and choose violence.

BEHAVIORAL NOTES

Temperament: Generally peaceful, but may become territorial toward similar fish in smaller aquariums.

Aiptasia Control: Often used to help reduce aiptasia populations, though individual results can vary. Some eat it readily, some need time, and some apparently missed the entire job interview.

Reef Compatibility: Best considered reef-safe with caution. Monitor closely around coral, clams, and ornamental invertebrates.

Feeding Behavior: May be shy at first. Once settled, they often become more active and comfortable picking around the rockwork.

Swimming Style: Filefish are slow, deliberate swimmers and prefer calmer areas of the aquarium.

Jumping: A tight-fitting lid is recommended. Fish continue to misunderstand the concept of staying inside the expensive glass box.

ACCLIMATION PROCESS

This acclimation method helps reduce stress by gradually introducing the fish to your aquarium’s temperature and water chemistry.

1. TURN OFF THE LIGHTS & ATO

Turn off aquarium lights to reduce stress. If you have an Auto Top Off system, switch it off before starting acclimation.

2. FLOAT THE BAG

Float the sealed bag in the aquarium for 15-20 minutes to allow the temperature in the bag to equalize with the tank.

3. OPEN BAG, ADD FISH TO CONTAINER

Carefully open the bag and transfer the fish and shipping water into a clean bucket or container.

4. ACCLIMATE USING TANK WATER

Add 1/4 cup of tank water to the container every 5 minutes for 40 minutes.

5. TRANSFER FISH TO AQUARIUM

Once acclimation is complete, use a net or specimen container to gently transfer the fish into the aquarium. Discard the shipping water. Do not pour shipping water into your aquarium.

6. REFILL THE AQUARIUM WITH SALTWATER

You may need to replace the saltwater removed during acclimation with fresh mixed saltwater.