How do I stop flatworms eating my Acropora?

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Levi Major advises on how to get rid of those coral-eating pests.

If you have seen coral-eating flatworms, I would recommend treating the affected coral in isolation, in the hope that the infection has not spread to other corals. You could attempt to cure the outbreak with wrasses from the Halichoeres or Psuedocheilinus genera, but I believe these will only keep the problem at bay.  

Your best bet for a complete cure would be to quarantine your corals and undertake dips. While freshwater dips could work, these are not the best option for SPS and should be limited to a maximum of 30 seconds in water closely matching the temperature and pH of the aquarium.

Better would be an iodine-based dip following the manufacturer’s recommendations.

As flatworms get deep into nooks and crannies within the coral, treatment may necessitate a small powerhead in the dip water to help wash them out.

Failing that, a gentle swish can help dislodge the more stubborn worms.

 copyright © Dr Kate Rawlinson

Several dips over several weeks may be needed to fully eradicate them. It should, however, be noted that most treatments will not deal with any egg sacs.

Attacked corals tend to show tissue recession from their base where you will see many little brown eggs. These can either be scraped off during dips, or any dead areas of the corals can be cut away to leave healthy tissue and any emergent flatworms dealt with during subsequent dips.

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