Freshwater Tropical
Columnaris
A highly contagious bacterial infection (Flavobacterium columnare) presenting as white/grey patches, often on the mouth, fins, or gills.…
Severe
Fish disease library
Browse every disease, parasite, and bacterial infection covered in our knowledge base. Pick filters to narrow it down — results update as you go.
16 conditions
Freshwater Tropical
Aeromonas (Ulcer Disease)
Bacterial infection causing open ulcers, hemorrhagic patches, and red sores. The #1 cause of mortality in koi ponds…
Critical
Freshwater Tropical
Mycobacteriosis (Fish Tuberculosis)
A slow, chronic infection caused by Mycobacterium spp. Symptoms include emaciation, spinal deformity, and granulomas. Zoonotic risk —…
Critical
Freshwater Tropical
Fin Rot
Progressive deterioration of fin tissue caused by opportunistic bacteria — usually a symptom of poor water quality.
Mild
Freshwater Tropical
Dropsy
Bloated body with pinecone-stuck-out scales — a symptom of organ failure, not a disease itself. Prognosis is generally…
Critical
Freshwater Tropical
Cloudy Eye
Hazy or opaque film over one or both eyes — usually a sign of bacterial infection or chronic…
Moderate
Freshwater Tropical
Streptococcosis
Bacterium disease of aquarium fish. Key signs: exophthalmia (often unilateral, 'pop-eye'), corneal opacity, spinning/spiral swimming, darkening, hemorrhages around…
Severe
Freshwater Tropical
Fin and Tail Rot
Bacterium (mixed/opportunistic) disease of aquarium fish. Key signs: ragged, frayed or eroded fin edges; white margins followed by…
Moderate
Freshwater Tropical
Motile Aeromonad Septicemia (Ulcer Disease)
Bacterium disease of aquarium fish. Key signs: open red ulcers (especially in koi), hemorrhagic skin patches, distended abdomen…
Moderate
Freshwater Tropical
Bacterial Cold Water Disease
Bacterium disease of aquarium fish. Key signs: rtfs in fry: spiral swimming, exophthalmia, dark colouration, anaemia, splenomegaly; older…
Moderate
Freshwater Tropical
Columnaris (Cotton-Wool Disease)
Bacterium disease of aquarium fish. Key signs: white-grey saddle-shaped lesion across back, frayed fins, mouth fungus-like white patches,…
Severe
Freshwater Tropical
Edwardsiellosis
Bacterium disease of aquarium fish. Key signs: gas-filled abscesses in muscle ('emphysematous putrefactive' lesions), ascites, exophthalmia, foul odour…
Moderate
Freshwater Tropical
Enteric Redmouth Disease (ERM)
Bacterium disease of aquarium fish. Key signs: subcutaneous hemorrhages around mouth and throat (the 'red mouth'), darkening, exophthalmia,…
Severe
Freshwater Tropical
Bacterial Kidney Disease (BKD)
Bacterium disease of aquarium fish. Key signs: chronic, progressive: granulomatous lesions in kidney (creamy white nodules), spleen, and…
Moderate
Freshwater Tropical
Enteric Septicemia of Catfish (ESC)
Bacterium disease of aquarium fish. Key signs: acute septicaemic: lethargy, head-up vertical floating, petechial hemorrhages on chin and…
Severe
Freshwater Tropical
Furunculosis
Bacterium disease of aquarium fish. Key signs: acute: rapid mortality without obvious external signs; chronic: characteristic 'furuncles' —…
Severe