About AEFW (Acropora-Eating Flatworms)

AEFW are species-specific flatworms that eat Acropora tissue. They blend with the coral perfectly when not moving. Symptoms: bite marks on Acropora tissue, pale or brown patches, base recession, and the flatworms themselves visible during dipping.

Causative organism: Amakusaplana acroporae

Severity: Moderate to severe

Symptoms

  • ✓ Bite marks on Acropora tissue
  • ✓ Pale or brown patches at branch tips
  • ✓ Base tissue recession
  • ✓ White egg patches near tissue (small clusters)
  • ✓ Slow STN that doesn't respond to parameter fixes

Treatment protocol

1

Dip every Acropora for inspection

Dip suspect colonies in coral dip (Bayer Advanced Insect Killer at 1ml/L, Coral Rx, ReVive). Watch the dip water for flatworms that fall off the coral.

2

Identify AEFW vs other flatworms

AEFW are 3-5mm long, oval, transparent with internal stomach contents visible (dark patch). They camouflage perfectly on Acropora. Different from harmless flatworms (red, larger, faster-moving).

3

Dip cycle every 5-7 days for 3 cycles

AEFW lay eggs that hatch over 7-10 days. Single dip kills adults but not eggs. Repeat 3 times to catch each hatchling generation as they reach dippable size.

4

Use a flatworm-eating wrasse for in-display control

Six-line wrasse, melanurus wrasse, mystery wrasse, and yellow coris wrasse eat flatworms in the display tank. Adding one helps prevent re-infestation between dip cycles.

5

Quarantine all new Acropora before adding to display

New SPS frags should be dipped and quarantined in a separate frag tank for 4-6 weeks before going into the display. AEFW that arrives on a $50 frag can wreck a $5,000 reef.

Quarantine prevents this

AEFW (Acropora-Eating Flatworms) is preventable in 95%+ of cases by running a 4-6 week quarantine on every new fish before introduction. Read the quarantine protocol.