Comprehensive pathogen, symptom, diagnosis and treatment guides for viral, bacterial, parasitic and fungal fish diseases - used by aquaculturists, veterinarians and hobbyists.
A myxozoan tissue parasite of Pacific salmon muscle causing grossly visible white milky cysts, rende...
A plerocercoid cestode (tapeworm) infection of freshwater fish, in which the large ribbon-like larva...
A poorly understood skin condition of farmed Atlantic salmon characterised by irregular red marks on...
Toxic accumulation of unionised ammonia (NH₃) in fish water causing gill damage, neurological dysfun...
A severe parasitic gill disease of sea-water Atlantic salmon caused by the marine amoeba Neoparamoeb...
A necrotising oomycete disease of freshwater and estuarine fish caused by Aphanomyces invadans, prod...
A chronic systemic bacterial disease of salmonids caused by Renibacterium salmoninarum, primarily af...
A lethal myxozoan gut disease of Pacific salmonids in the Columbia River basin caused by Ceratomyxa...
A highly lethal herpesviral disease of juvenile channel catfish caused by Ictalurid herpesvirus 1, c...
A parasitic ciliate infection of the skin and gills of freshwater fish caused by Chilodonella spp.,...
Acute and chronic gill damage from unneutralised chlorine or chloramine in aquarium water - one of t...
Acute toxicity from copper ions - fatal to invertebrates at trace levels and to fish at moderate lev...
A haemoflagellate blood parasite disease of Pacific salmonids caused by Cryptobia salmositica, trans...
A herpesviral disease of goldfish and crucian carp causing severe haematopoietic necrosis, gill dama...
The most economically important disease of the US channel catfish aquaculture industry, causing ente...
A severe iridoviral disease endemic to Australia, causing massive necrosis of haematopoietic tissues...
A systemic fungal infection of fish caused by black yeast-like fungi of the genus Exophiala, causing...
Rainbow Trout Fry Syndrome (RTFS) and Bacterial Cold Water Disease (BCWD) in salmon — two manifestat...
A monogenean ectoparasite devastating to naive Atlantic Salmon populations, causing hyperinfection a...
Toxic H2S gas produced by anaerobic bacteria in deep sand beds - can kill entire tanks if released s...
A protozoan ectoparasite infection caused by the flagellate Ichthyobodo necator, attaching to skin a...
The most common and devastating freshwater fish disease globally — caused by the holotrophic ciliate...
A rhabdoviral disease causing haematopoietic (blood-forming tissue) necrosis in salmonids, particula...
A severe viral disease of Atlantic Salmon caused by ISAV, characterised by high mortality in sea-wat...
The most devastating viral disease of farmed Atlantic salmon - a WOAH-notifiable pathogen requiring...
A herpesvirus with 90%+ mortality in koi and common carp populations - one of the greatest threats t...
A highly contagious and lethal herpesviral disease of koi and common carp, causing mass mortality at...
A gram-positive bacterial septicaemia of fish caused by Lactococcus garvieae, causing haemorrhagic s...
Suffocation from insufficient dissolved oxygen in the water - fish visible gasping at the surface is...
A nutritional disorder in salmonid offspring caused by maternal thiamine (Vitamin B1) deficiency, re...
A highly lethal dinoflagellate parasite of marine fish - one of the most dangerous marine aquarium d...
An incurable microsporidian parasite of small tetras - progressive muscle wasting and color loss lea...
Poisoning by elevated nitrite in water, which enters fish gills and oxidises haemoglobin to methaemo...
Viral Nervous Necrosis - a devastating disease of marine fish larvae causing near-total mortality in...
A dinoflagellate ectoparasitic disease causing a characteristic golden-yellow "velvet" or "rust" dus...
Mass mortality or sublethal physiological stress in fish caused by insufficient dissolved oxygen in...
An acute or subacute bacterial septicaemia of marine fish caused by Photobacterium damselae subsp. p...
Physiological damage or death in fish caused by exposure to acidic water (low pH), impairing ion reg...
Osmotic and metabolic disruption from sudden pH changes greater than 0.3 units - a leading cause of...
A salmonellosis-like rickettsial disease of salmonids caused by the obligate intracellular bacterium...
A severe iridoviral disease of marine fish caused by Red Sea Bream Iridovirus, a Megalocytivirus cha...
A water mould (oomycete) infection producing characteristic white-grey cotton-wool tufts on the skin...
A rhabdoviral haemorrhagic disease of cyprinids occurring primarily in spring when water temperature...
A WOAH-notifiable rhabdovirus of common carp and koi, causing haemorrhagic septicaemia at spring tem...
An emerging viral disease of tilapia causing syncytial encephalitis and high mortality, spreading ra...
A mysterious ulcerative skin disease of adult returning Atlantic Salmon in UK and Irish rivers, prod...
A WOAH-notifiable viral disease with major impact on wild Great Lakes fish since 2005.
A nodaviral disease causing vacuolating encephalopathy and retinopathy (VER) in larval and juvenile...
A motile Aeromonas septicaemia (MAS) caused by Aeromonas hydrophila, an opportunistic pathogen that...
A bacterial septicaemia and haemorrhagic disease - one of the most common opportunistic pathogens of...
Chemical burn of gill tissue caused by ammonia in the water - the leading cause of fish death in new...
A protozoan gill infection - the leading disease problem in Tasmanian and increasingly Norwegian sal...
A slow-growing bacterial infection of salmonid kidneys - one of the harder-to-treat farmed salmon di...
A oomycete infection causing necrosis and rotting of gill tissue, associated with warm, oxygen-deple...
Red nematode worms protruding from the fish anus - increasingly common in imported aquarium fish.
A chronic cardiomyopathy of large sea-water farmed Atlantic salmon caused by PMCV, characterised by...
A ciliate parasite causing heavy mucus overproduction and gill damage - often lethal in weakened fis...
A gram-negative bacterial disease appearing as cotton-like patches on body/gills - can kill within 2...
A gram-negative bacterial disease causing cotton-wool-like yellow lesions on the skin, gills, and fi...
A microscopic protozoan parasite causing gill and skin damage - one of the deadliest freshwater para...
A symptom cluster of severe internal disease - fluid accumulation in the body cavity causing pinecon...
The primary bacterial killer of farmed catfish - enteric septicaemia (ESC).
A systemic Yersinia infection of salmonids characterised by reddening of the mouth, jaw, and opercul...
A fungal-like oomycete causing deep ulcers in wild and farmed fish across Southeast Asia and Africa.
The freshwater gram-negative bacterial disease causing cotton-like patches on fins, mouth, and gills...
An emerging granulomatous disease of fish caused by the intracellular bacterium Francisella, forming...
A historic bacterial killer of farmed salmonids - one of the diseases whose effective vaccination tr...
Freshwater white spot disease - the most common freshwater aquarium parasite. Life cycle-dependent t...
A birnaviral disease of salmonids causing necrosis of pancreatic acinar tissue and severe enteritis...
A saltwater ciliate parasite causing white spots on skin and gills - the saltwater equivalent of fre...
A chronic, wasting bacterial disease - one of the few fish diseases that can also infect humans (ski...
Nitrite in the water binds fish hemoglobin, forming methemoglobin - preventing oxygen transport and...
Bubbles forming under fish skin and inside organs from supersaturated dissolved gas - hidden hazard...
A chronic granulomatous disease of marine fish caused by the filamentous bacterium Nocardia seriolae...
A dinoflagellate parasite causing gold-dust appearance on fish - the freshwater equivalent of marine...
Pancreas Disease - a viral condition affecting the pancreas of farmed Atlantic salmon in Northern Eu...
Heart and Skeletal Muscle Inflammation (HSMI) - a viral disease of farmed salmon causing chronic mor...
A chronic wasting bacterial disease - among the few fish diseases that also transmits to humans (fis...
A myxozoan kidney disease of salmonids causing massive proliferation of lymphocytes and monocytes in...
An alphaviral disease of farmed Atlantic salmon characterised by pancreatic necrosis, cardiomyopathy...
The principal ectoparasite of farmed Atlantic salmon in the North Atlantic, causing skin lesions and...
The parasitic copepods that plague farmed salmon and transmit to wild populations - the #1 environme...
The dominant bacterial disease of farmed tilapia globally - responsible for major losses in Asian an...
Physiological stress or death from temperature changes exceeding 5 F within a short window.
A marine bacterial disease causing extensive superficial ulcerative lesions on the skin, fins, and m...
Physiological dysfunction and mortality caused by water temperatures exceeding (or falling below) th...
The major bacterial disease of marine fish farming - particularly Atlantic salmon post-smolt and sea...
A myxozoan parasite of trout causing skeletal deformity and characteristic tail-chasing behaviour.
A parasitic copepod whose females anchor into the muscle of fish using forked head appendages, causi...
A copepod that embeds anchor-shaped attachment into fish skin - visible as small dangling threads on...
A visible parasitic copepod that anchors into the fish body wall - common in outdoor ponds and koi.
A branchiuran crustacean ectoparasite that attaches to the skin of freshwater fish, causing puncture...
A bacterial gill disease of salmonids caused by Flavobacterium branchiophilum, characterised by lame...
Gill-specific bacterial infection of juvenile salmonids - a major hatchery disease.
A nematode intestinal parasitic infection of freshwater fish caused by Camallanus species, with worm...
Internal red nematode worms visible protruding from the fish anus - increasingly common in imported...
A poxviral disease of koi and common carp characterised by lethargy, oedema of gills and skin, and t...
A herpesvirus causing wax-like skin growths in carp and goldfish - unsightly but rarely fatal.
A cyanobacterial (blue-green algae) bloom - not a true algae but a bacterial mat coating surfaces, r...
Monogenean trematodes that parasitise the gills of freshwater fish, causing irritation, mucus hyperp...
A digenean trematode whose metacercaria accumulate in the lens of fish eyes, causing cataracts and b...
A bacterial disease caused by Edwardsiella tarda causing internal abscesses, gas-filled lesions, and...
A ciliate ectoparasitic infection of fish skin and fins caused by stalked peritrich protozoans of th...
A parasitic copepod infection of fish gills caused by female Ergasilus copepods, which attach perman...
Physical injuries from aggressive tankmates - the most preventable form of aquarium injury.
Bacterial infection causing progressive erosion of fins - one of the most common aquarium diseases,...
Flat, disc-shaped parasitic crustaceans that attach externally to fish and feed on blood.
Large visible crustacean parasites that attach to fish and suck blood - primarily a pond fish proble...
Monogenean flatworm parasites of the gills - cause respiratory distress and secondary bacterial infe...
Progressive erosion of the head and lateral line pores - primarily nutritional/environmental, not pu...
A reoviral disease of farmed Atlantic salmon causing inflammation of the heart and red skeletal musc...
A chronic parasitic condition of cichlids and other tropical freshwater fish caused by flagellate pr...
Progressive pitting erosion of the head and lateral line - typically linked to Hexamita parasites, n...
A systemic infection caused by the mesomycetozoean Ichthyophonus, forming granulomatous cysts throug...
Myxozoan parasites that infect fish muscle - not directly pathogenic but cause post-harvest muscle l...
A myxozoan parasite that invades the muscle of marine fish, releasing enzymes post-mortem that cause...
Deposition of calcium carbonate and calcium phosphate crystals in the kidney tubules of fish exposed...
Chronic effects of elevated nitrate levels - though less immediately toxic than ammonia, prolonged e...
Opacification of the lens of the eye in farmed salmonids, primarily caused by dietary deficiency (es...
The chronic decline of poorly-maintained freshwater tanks - accumulated nitrate and mineral depletio...
Abnormal protrusion of one or both eyes - either from injury (unilateral) or systemic infection (bil...
A gram-negative bacterial infection often secondary to injury or gill damage - common in aquarium fi...
An opportunistic bacterial septicaemia caused by Pseudomonas species, typically striking immunocompr...
A common fungal-like infection - white cottony growth on damaged skin, gills, or fish eggs. Actually...
A togaviral disease of freshwater rainbow trout characterised by fish lying on their sides at the po...
A disorder of swim bladder function causing buoyancy problems - most common in fancy goldfish due to...
A ciliate parasite of stressed freshwater fish, especially guppies - often called "guppy disease".
A saucer-shaped ciliate parasite common in poor water quality - visible under microscope as a rotati...
A zoonotic nematode larva found coiled in the muscle and viscera of marine fish; causes anisakiasis...
An iridoviral disease characterised by dramatic hypertrophy of individual infected cells (fibroblast...