Parasitic
🟡 Moderate
✓ Treatable
Dactylogyrus (Gill Fluke)
🦠 Dactylogyrus spp. (>400 species) · Dactylogyridae (Monogenea)
📋 Definition
Monogenean trematodes that parasitise the gills of freshwater fish, causing irritation, mucus hyperproduction, and respiratory distress, especially in fry.
📊 Key Facts
Causative Agent
Dactylogyrus spp. (>400 species)
Agent Family
Dactylogyridae (Monogenea)
Geographic Range
Worldwide — freshwater fish
Transmission Routes
Egg-borne (oviparous) — eggs in water
Primary Host
Cyprinids, salmonids, channel catfish
Vaccine
✗ None / Experimental
🩺 Clinical Signs
Increased gill movement, gaping at surface, pale/swollen gills, excess mucus on gills, loss of appetite, mortalities in heavy infestations.
🔬 Symptoms
🔬
Increased gill movement
Respiratory Acute
🔬
Pale swollen gills
Respiratory Subacute
🔬
Gaping at water surface
Respiratory Acute
🧪 Diagnosis
Wet mount of gill biopsy — characteristic opisthaptor with anchors and hooks, eyespots (Dactylogyrus is oviparous).
💊 Treatment
Praziquantel, formalin, potassium permanganate.
🛡️ Prevention
ℹ️ Prevention is the most effective strategy for managing this disease in aquaculture and aquarium settings.
Quarantine new fish, maintain water quality.