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
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.
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).
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.
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.
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.
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.
Whatever specific topic brought you here, four fundamentals govern long-term aquarium success: water quality, parameter stability, biological filtration, and species-appropriate husbandry. Skip any one and the others struggle to compensate.
Water quality: ammonia + nitrite at zero, nitrate under 30 ppm freshwater + 10 ppm reef. Test weekly with API or Salifert kits. Use our water parameter checker to score your readings against your tank type.
Parameter stability: stable wrong parameters beat fluctuating ideal parameters. Most fish tolerate a wide pH range if it's stable. Sudden swings of 0.4+ pH or 5+°F kill fish faster than chronic suboptimal values. Use temperature controllers (Inkbird) + automated dosing for consistency.
Biological filtration: the bacterial colony on your filter media + rock + substrate is the engine. Never replace all media at once. Use our filter turnover calculator to size correctly.
Species-appropriate husbandry: research adult size, territoriality, diet, and tankmate compatibility before purchase. Use our tank stocking calculator + compatibility guides.
How long does an aquarium take to set up? 4-6 weeks for full cycling + first stocking. Use our cycle ETA calculator + how long does cycling take.
What's the best aquarium for beginners? 20-gallon long. Big enough for parameter stability, small enough for budget + space. See beginner picks.
How often should I do water changes? 25-30% weekly. See water change frequency Q&A + water change calculator.
Why does my fish keep dying? 5 leading causes: uncycled tank, wrong species pairings, no quarantine, undersized tank, neglected water-change schedule. See full diagnosis.
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