Goldfish
Fungal Diseases in Koi & Goldfish
Fungal diseases — most commonly caused by water moulds of the genus Saprolegnia — are a frequent secondary…
Moderate
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
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
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
Goldfish
White Tail Disease in Koi & Goldfish
White tail disease is a serious and poorly understood condition caused by microsporidian intracellular parasites that destroy muscle…
Moderate To To To Severe
Freshwater Tropical
Columnaris
A highly contagious bacterial infection (Flavobacterium columnare) presenting as white/grey patches, often on the mouth, fins, or gills.…
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
Mycobacteriosis (Fish Tuberculosis)
A slow, chronic infection caused by Mycobacterium spp. Symptoms include emaciation, spinal deformity, and granulomas. Zoonotic risk —…
Critical
Freshwater Tropical
Cloudy Eye
Hazy or opaque film over one or both eyes — usually a sign of bacterial infection or chronic…
Moderate
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
Velvet (Oodinium)
Dinoflagellate parasite producing a fine, gold-dust coating across the body. More lethal than ich; gill infection causes rapid…
Severe
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
Costia (Ichthyobodo)
Parasite (flagellated protozoan) disease of aquarium fish. Key signs: blue-grey film of mucus over skin ('slime disease'), peeling…
Moderate