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
Brackish Water 2 Freshwater Tropical 46 Goldfish 29 Koi 4 Koi & Pond 24 Marine / Saltwater 13
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
Severity
Critical 20 Mild 2 Mild To To To Severe 1 Moderate 22 Moderate To To To Severe 2 Severe 9

11 conditions

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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

Freshwater Tropical

Hexamita (Hole-in-the-Head)

Intestinal flagellate parasite causing pitted lesions on the head and lateral line, especially in cichlids and discus. Often…

Moderate

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