Goldfish
Parasitic Diseases in Koi & Goldfish
Parasitic infestations represent one of the most diverse disease categories in ornamental fish keeping. From the microscopic ciliate…
Mild 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
Koi & Pond
Koi Herpes Virus (KHV)
Notifiable viral disease devastating koi populations worldwide. Mortality 80–100%. No cure — only management and prevention.
Critical
Freshwater Tropical
Swim Bladder Disorder
Loss of buoyancy control — fish floats, sinks, or swims at odd angles. Common in fancy goldfish and…
Moderate
Freshwater Tropical
Lymphocystis Disease
Virus disease of aquarium fish. Key signs: wart-like, cauliflower-shaped, pinkish-white nodules on skin and fins (greatly enlarged virus-infected…
Mild
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
Goldfish
Spring Viremia of Carp (SVC)
Virus disease of aquarium fish. Key signs: lethargy, darkening, exophthalmia, distended abdomen (dropsy), petechial hemorrhages in skin and…
Critical
Freshwater Tropical
Infectious Salmon Anemia (ISA)
Virus disease of aquarium fish. Key signs: pale gills, ascites, dark liver, pinpoint hemorrhages in viscera and eye;…
Critical
Brackish Water
Epizootic Ulcerative Syndrome (EUS)
Oomycete disease of aquarium fish. Key signs: deep, red, necrotic skin ulcers (often on flanks); mycotic granulomas in…
Critical