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
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.
Fish type
Symptom
Bloated Abdomen 2
Bloated belly 2
Clamped Fins 3
Cloudy Eye 1
Color Fading 1
Cotton Like Growth 1
Cottony Tufts 2
Darkened color 4
Dropsy 1
Emaciation 4
Erratic Swimming 7
Excess Mucus 3
Eye Discharge 1
Fin Erosion 1
Fin Rot 3
Fin Whitening 1
Flashing 4
Flashing / rubbing 8
Floating 1
Frayed Fins 6
Gasping at surface 4
Gill Damage 1
Gold Dust Coating 1
Gold-dust film 1
Granulomas / nodules 3
Head Pitting 1
Hemorrhage 1
Hemorrhaging 13
Lateral Line Erosion 1
Lethargy 19
Listless near bottom 1
Loss Of Appetite 7
Loss Of Balance 1
Mouth Erosion 1
Open Sores 4
Pale Gills 4
Pinecone Scales 1
Pop Eye 17
Rapid breathing 4
Rapid Gilling 4
Red Fin Bases 1
Red Ulcers 2
Scale Loss 1
Scratching 3
Sinking 1
Skin Erosion 1
Skin lesions 4
Spinal Deformity 2
Sudden death 3
Sunken Eyes 1
Swimming Sideways 1
Tissue necrosis 8
Ulcers 1
Visible parasite 1
Wart-like growths 2
White Fin Edges 1
White Grey Patches 1
White Patches 1
White Patches Gills 1
White Spots 5
White Stringy Feces 1
White Tail 1
Cause
Aeromonas hydrophila 1
Aphanomyces spp. 1
Argulus spp. 1
Bacteria 16
Branchiomyces spp. 1
Columnaris 1
Dactylogyrus spp. 1
Environmental 2
Fungus 3
Ichthyophthirius multifiliis 1
Lernaea spp. 1
microsporidian 1
Parasite 18
Pleistophora hyphessobryconis 1
Pseudoloma neurophilia 1
Pseudomonas fluorescens 1
Saprolegnia spp. 1
Trichodina spp. 1
Virus 14
Freshwater Tropical
Fin Rot
Progressive deterioration of fin tissue caused by opportunistic bacteria — usually a symptom of poor water quality.
Mild
Freshwater Tropical
Cloudy Eye
Hazy or opaque film over one or both eyes — usually a sign of bacterial infection or chronic…
Moderate
Freshwater Tropical
Branchiomycosis (Gill Rot)
Fungus (true fungus) disease of aquarium fish. Key signs: rapid breathing, gasping at surface, gill necrosis with white/marbled…
Severe
Freshwater Tropical
Hole-in-the-Head Disease (Hexamita)
Parasite (flagellated protozoan) disease of aquarium fish. Key signs: pinhole-sized pits on head that enlarge into cavities; lesions…
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
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
Largemouth Bass Virus (LMBV) Disease
Virus disease of aquarium fish. Key signs: trouble maintaining equilibrium (swim bladder distension), surfacing, occasional die-offs of trophy-size…
Critical
Freshwater Tropical
Epizootic Hematopoietic Necrosis (EHN)
Virus disease of aquarium fish. Key signs: sudden mortality; focal liver necrosis, splenomegaly, hemorrhages in kidney.
Critical