Gill Fluke (Monogenean Infection)

About this condition

An infestation by monogenean trematodes such as Gyrodactylus and Dactylogyrus on the gills and body surface. Heavy gill infestation can cause respiratory distress, and severe cases may lead to weakness and death.

Common symptoms

• Rapid gill movement or open-mouth breathing observed
• Fish gasping at the water surface
• Fish rubbing against substrate or decorations
• Loss of appetite, lethargy, and progressive weakness

Common causes

• Parasitism by monogenean trematodes such as Gyrodactylus and Dactylogyrus
• Introduction via unquarantined newly added fish
• Stress from water quality deterioration or sudden temperature changes
• Rapid spread of infection in overcrowded conditions

Prevention (husbandry & daily care)

Thoroughly quarantining new fish and being careful when introducing live food or external water are key preventive measures. Maintain good water quality through proper filter management and regular water changes.

Related species guide

When to see a vet

What can a specialist store do?

A specialist aquarium store will evaluate the condition of the gills and water quality data to assess the likelihood and severity of infestation, advising on isolation, water quality improvement, and the appropriate course of action. Aquatic-animal veterinarians are limited in number, but facilities equipped with microscopy can provide more precise identification of the monogenean species involved.

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