Severe

Freshwater Tropical

Columnaris

A highly contagious bacterial infection (Flavobacterium columnare) presenting as white/grey patches, often on the mouth, fins, or gills.…

Severe

Marine / Saltwater

Marine Ich (Cryptocaryon irritans)

Saltwater white-spot disease. A 2006 resistant strain renders traditional copper and formalin treatments ineffective — quinine sulfate is…

Severe

Freshwater Tropical

Velvet (Oodinium)

Dinoflagellate parasite producing a fine, gold-dust coating across the body. More lethal than ich; gill infection causes rapid…

Severe