Parasitic
🟡 Moderate
✓ Treatable
Argulosis (Fish Louse)
🦠 Argulus foliaceus, A. japonicus · Argulidae (Branchiura)
📋 Definition
A branchiuran crustacean ectoparasite that attaches to the skin of freshwater fish, causing puncture wounds, haemorrhage, stress, and virus transmission.
📊 Key Facts
Causative Agent
Argulus foliaceus, A. japonicus
Agent Family
Argulidae (Branchiura)
Geographic Range
Worldwide — freshwater fish
Transmission Routes
Free-swimming juveniles attach to fish
Primary Host
Cyprinids, salmonids — wide freshwater host range
Vaccine
✗ None / Experimental
🩺 Clinical Signs
Flattened disc-like parasites (5–10 mm) visible on skin; skin haemorrhages; flashing; restless behaviour; secondary infections at wound sites.
🔬 Symptoms
🔬
Visible disc-like parasites
Integumentary Chronic
🔬
Skin haemorrhages
Integumentary Acute
🔬
Flashing behaviour
Behavioural Acute
🧪 Diagnosis
Visual identification of adult parasites on fish.
💊 Treatment
Organophosphate bath (dichlorvos), diflubenzuron.
🛡️ Prevention
ℹ️ Prevention is the most effective strategy for managing this disease in aquaculture and aquarium settings.
Screen water inflows, quarantine new fish.