Argulus (fish lice) are visible flat parasitic crustaceans (4-8mm) attached to fish skin. Common in koi ponds + outdoor goldfish. Treatment: organophosphate or manual removal.
Argulus parasites contracted from outdoor water sources or imported pond fish. Usually visible to naked eye.
Always treat in a separate quarantine tank. Most medications are toxic to coral, invertebrates, and live rock biology.
Quarantine pond fish. Avoid wild caught + add UV sterilizer to pond.
Browse the full disease database for 45 aquarium conditions with treatment protocols, or check the care library for prevention-focused husbandry guides. Use our symptom matcher to rank likely diseases from observed signs, the water parameter checker to diagnose related water-quality issues, or the QT timeline calculator to plan a treatment schedule.