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

24 conditions

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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

Fin Rot

Progressive deterioration of fin tissue caused by opportunistic bacteria — usually a symptom of poor water quality.

Mild

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

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

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

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

Brackish Water

Marine Velvet (Amyloodinium)

Parasite (dinoflagellate) disease of aquarium fish. Key signs: dusty gold-brown coating on skin and gills, rapid respiration, gasping…

Moderate