Disease library

Fish disease library

Every disease, parasite, and infection in our knowledge base. Tap the keywords to narrow the list — the page updates with a clean, shareable URL.

4 conditions

Clear all filters

Goldfish

Bacterial Diseases in Koi & Goldfish

Bacterial diseases are among the most common and serious health challenges facing koi and goldfish keepers worldwide. Caused…

Moderate To To To Severe

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

Fin Rot

Progressive deterioration of fin tissue caused by opportunistic bacteria — usually a symptom of poor water quality.

Mild