parasite · saltwater tank

AEFW (Acropora-Eating Flatworms)

AEFW (Amakusaplana acroporae) are tan flatworms ~3-5mm that feed exclusively on Acropora tissue. Bite marks appear as small white spots; advanced infestation strips tissue + leaves bare skeleton.

Reviewed by Fast Aquatics husbandry team · Updated May 2026

Severity: Critical for Acropora collections - can wipe out colonies in months

Symptoms

Small white bite spots on Acropora flesh
Tan flatworms visible after a turkey-baster blast
Tissue recession in patches
Brown egg clusters at coral base

What causes it

Hitchhiked on un-dipped Acropora frags. Eggs are hard to dip off; flatworms can hide for weeks before symptoms appear.

Treatment options

Always treat in a separate quarantine tank.

Bayer Advanced dip cycle. Dip every 5 days for 4-5 cycles to break the egg-hatch cycle. Most reliable treatment.

Sixline / leopard wrasse predators. Some wrasses pick AEFW off Acropora over time. Long-term control rather than treatment.

Manual egg removal. Scrape brown egg clusters off the coral base after dipping. Reduces re-infestation rate.

Prevention

Dip every new Acropora frag for 5+ minutes in CoralRx or Bayer Advanced. Quarantine SPS in a separate tank for 30 days.

Frequently asked questions

What does AEFW (Acropora-Eating Flatworms) look like?

Small white bite spots on Acropora flesh. Tan flatworms visible after a turkey-baster blast. Tissue recession in patches.

What causes AEFW (Acropora-Eating Flatworms)?

Hitchhiked on un-dipped Acropora frags. Eggs are hard to dip off; flatworms can hide for weeks before symptoms appear.

How is AEFW (Acropora-Eating Flatworms) treated?

Bayer Advanced dip cycle: Dip every 5 days for 4-5 cycles to break the egg-hatch cycle. Most reliable treatment.

Can AEFW (Acropora-Eating Flatworms) be prevented?

Dip every new Acropora frag for 5+ minutes in CoralRx or Bayer Advanced. Quarantine SPS in a separate tank for 30 days.

How fatal is AEFW (Acropora-Eating Flatworms)?

Critical for Acropora collections - can wipe out colonies in months

Browse the full disease database for 45 aquarium conditions with treatment protocols, or check the care library for prevention-focused husbandry guides. Use our symptom matcher to rank likely diseases from observed signs, the water parameter checker to diagnose related water-quality issues, or the QT timeline calculator to plan a treatment schedule.