Identifying Argulus
Flat, disc-shaped parasite 4-6mm wide. Greenish-grey. Visible suction cups when removed.
Fish scratch against décor, develop ulcers where parasites attach.
Manual Removal
Sedate fish with clove oil. Use forceps to gently lift parasite — they release suction with persistent pressure.
Disinfect wound site with iodine.
Medication
Dimilin (diflubenzuron) — most effective, treats eggs too.
Potassium permanganate dip for severe cases.
Cyromazine (Larva-X) is also effective.
- ✦Pond treatments must extend across whole pond — argulus eggs scatter in substrate
- ✦Repeat treatment every 14 days for 3 cycles
- ✦Test water — argulus thrives in poor conditions
Prevention
Always quarantine new pond fish 4+ weeks. Argulus often comes in with new koi or goldfish.
Annual pond preventive treatment is wise in regions with wild bird traffic — birds can transfer parasite eggs.