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
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
Goldfish
Fungal Diseases in Koi & Goldfish
Fungal diseases — most commonly caused by water moulds of the genus Saprolegnia — are a frequent secondary…
Moderate
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
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
Streptococcosis
Bacterium disease of aquarium fish. Key signs: exophthalmia (often unilateral, 'pop-eye'), corneal opacity, spinning/spiral swimming, darkening, hemorrhages around…
Severe
Goldfish
Anchor Worm (Lernaea)
Parasite (copepod crustacean) disease of aquarium fish. Key signs: greenish-white thread-like worms protruding from skin (the female parasite…
Moderate
Freshwater Tropical
Motile Aeromonad Septicemia (Ulcer Disease)
Bacterium disease of aquarium fish. Key signs: open red ulcers (especially in koi), hemorrhagic skin patches, distended abdomen…
Moderate
Freshwater Tropical
Saprolegnia (Cotton Mold)
Oomycete disease of aquarium fish. Key signs: cotton-wool-like white or grey patches on skin, fins or eggs, often…
Moderate
Freshwater Tropical
Whirling Disease
Parasite (myxosporean) disease of aquarium fish. Key signs: whirling (tail-chasing) behaviour, blackened tail, skeletal deformities (cranial deformations, scoliosis)…
Critical
Freshwater Tropical
Bacterial Cold Water Disease
Bacterium disease of aquarium fish. Key signs: rtfs in fry: spiral swimming, exophthalmia, dark colouration, anaemia, splenomegaly; older…
Moderate