Coral Pest Identification and Removal Guide | How to Distinguish Flatworms, Nudibranches, and Red Bugs
A guide to identifying and removing parasitic pests on corals. Preventive dipping procedures are also included.
Key Takeaways
A guide to identifying and removing parasitic pests on corals. Preventive dipping procedures are also included.
Coral Pest Identification and Removal Guide | How to Distinguish Flatworms, Nudibranches, and Red Bugs
One of the greatest threats to coral keeping is the presence of "pests" that are easily overlooked by the naked eye. Small organisms such as flatworms, nudibranchs, and red bugs can multiply explosively in the tank if discovered late, potentially decimating an entire collection. However, if you know the characteristics and handling methods for each pest in advance, you can minimize damage. This article provides a detailed explanation of how to identify major coral pests and the specific removal protocols to use.
Key Characteristics of 4 Major Pest Species You Should Know
AEFW (Acropora Eating Flatworm)
AEFW stands for "Acropora Eating Flatworm," a flatworm that primarily parasitizes Acropora (staghorn coral). With a body length of approximately 3-6mm, it is extremely difficult to spot even for experienced keepers because it camouflages itself to match the color of its host coral.
Signs of infestation include irregular white feeding scars appearing on the coral tissue and polyps that remain constantly retracted. As the infection progresses, "tissue necrosis" spreads rapidly, and in severe cases, entire branches can be reduced to bare skeleton within days.
To confirm infestation, remove the coral from the tank and perform a dip treatment using freshwater or medicated dip solutions. You can assess whether infection is present by observing parasites that fall onto a white container. Make it a habit to always dip new Acropora corals in isolation before returning them to the main tank.
Montipora-Eating Nudibranch
A small nudibranch that feeds on corals of the Montipora genus, with a body length of approximately 2-5mm. It has a white or translucent body color and spends the day attached to the coral surface, directly consuming polyps. Both adult nudibranchs and white egg clusters laid in the skeleton gaps must be removed.
Signs include the Montipora surface turning partially white or white egg clusters appearing on the skeleton. Careful observation using a magnifying glass or underwater light is effective. Adults can be physically removed with a soft brush or tweezers, but eggs are resistant to medications and require repeated treatment.
