Brooklynelliasis / Clownfish Disease

About this condition

An infection caused by the ciliate protozoan Brooklynella hostilis, most commonly seen in clownfish. It produces excessive mucus secretion and skin sloughing, and can progress rapidly to a severe state.

Common symptoms

• Cloudy skin surface and excessive mucus secretion
• Sloughing of skin and scales
• Rapid breathing and open-mouth respiration
• Lethargy and complete loss of appetite

Common causes

• Infestation by the ciliate Brooklynella hostilis
• Introduction of new clownfish without quarantine treatment
• Stress from transport or sudden environmental changes
• Weakened immunity from poor water quality or overcrowding

Prevention (husbandry & daily care)

Always quarantine new clownfish in a treatment tank for a sufficient period. Minimize post-transport stress and maintain stable temperature, salinity, and water quality.

Related species guide

When to see a vet

What can a specialist store do?

Since veterinary clinics experienced with marine fish are limited, prioritizing consultation with a specialist store knowledgeable in clownfish care is recommended. Because the disease progresses rapidly, early guidance on isolation and appropriate treatment procedures is important.

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