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
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
Freshwater Ich (White Spot Disease)
The most common freshwater fish disease. Tiny white spots resembling grains of salt cover the body and fins.
Moderate
Freshwater Tropical
Velvet (Oodinium)
Dinoflagellate parasite producing a fine, gold-dust coating across the body. More lethal than ich; gill infection causes rapid…
Severe
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
Fin Rot
Progressive deterioration of fin tissue caused by opportunistic bacteria — usually a symptom of poor water quality.
Mild
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
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
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
Freshwater Tropical
Epizootic Hematopoietic Necrosis (EHN)
Virus disease of aquarium fish. Key signs: sudden mortality; focal liver necrosis, splenomegaly, hemorrhages in kidney.
Critical