Freshwater Tropical
Fin Rot
Progressive deterioration of fin tissue caused by opportunistic bacteria — usually a symptom of poor water quality.
Mild
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
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
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
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
Costia (Ichthyobodo)
Parasite (flagellated protozoan) disease of aquarium fish. Key signs: blue-grey film of mucus over skin ('slime disease'), peeling…
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
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
Freshwater Tropical
Freshwater Velvet (Gold Dust Disease)
Parasite (dinoflagellate) disease of aquarium fish. Key signs: fine yellow to gold dusty coating on skin (gives 'velvety'…
Moderate
Marine / Saltwater
Marine Ich (Cryptocaryon irritans)
Parasite (ciliate protozoan) disease of aquarium fish. Key signs: white spots (larger and more diffuse than freshwater ich),…
Moderate
Freshwater Tropical
Ich (White Spot Disease)
Parasite (ciliate protozoan) disease of aquarium fish. Key signs: small pinhead-sized white spots (cysts) on skin and fins;…
Moderate
Freshwater Tropical
Ceratomyxosis
Parasite (myxosporean) disease of aquarium fish. Key signs: distended abdomen, ascites, hemorrhagic enteritis, lethargy, blackened tail, anaemia; chronic…
Critical
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