Wanted: Acropora-eating flatworms

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Have you had experience of Acropora-eating flatworms in your reef tank? A collaboration between two UK universities and a US one are currently describing a new species of flatworm that eats Acropora coral and are appealing to hobbyists to help them.

The Acropora-eating flatworm (AEFW) is a newly discovered species of polyclad flatworm currently being described by scientists at University College London, Cambridge University and University of Houston.

It was discovered in aquaria in the USA feeding on endangered and vulnerable Acropora species, such as A. valida, A. pulchra and can cause the death of the entire colony.

Coral conservationists and aquarists are keen to understand the biology and life history of this predator.

The universities are asking for any recorded instances of this animal in coral tanks housing Acropora sp. within the UK and Europe and also for any sightings of this worm in the wild.

Adult worms (above) are up to 10mm long and 5-6mm wide, they camouflage very well against the coral due to the presence of coral tissue and zooxanthellae in their highly branched gut.

Feeding scars on the coral tissue and egg batches on the bare coral skeleton are generally the first indication that the worms are present.

An adult can lay multiple batches of eggs which contain between 20-30 egg capsules and each capsule houses between 3-7 embryos.

Researchers do not know what their predators may be in the wild and hypothesise that perhaps their predators are not found in aquaria, which allows their numbers to grow and consequently leading to lethal levels of tissue damage and loss to the coral colony.

If you have any information on the distribution of these animals, please contact:

Dr Kate Rawlinson
Department of Genes, Evolution and Environment,
University College London,
Gower St. London. WC1E6BT
e-mail: [email protected]