Symptoms - Probable Cause

Small white spots on fins or skin - White spot (Cryptocaryon)

Fine whitish peppery coating on fins or skin - Velvet (Amyloodinium)

Spawn-like gray-white patches on fins or skin - Lymphocystis

Cauliflower-like patches on fins or skin - Lymphocystis (later stage)

Larger "tapioca" patches on fins of skin - Myxosporiasis (Henneguya)

Blue-white or pinkish patches on skin - Ciliates

Red streaks on body or fins - Bacterial septicemia

Tattered fins or tail (fin or tail-rot) - Bacterial septicemia (later stage)

Red-ringed craters on skin - Argulus bites

Irregular bulges (cysts) under skin - Microporiasis

Swellings on body or base of fins - Tumors or Sporozoans

Yellow-to-black cysts up to 1/5 in. bursting through body - Ichthyophonus - White spot disease is caused by a parasite that attacks all freshwater and saltwater fish species. The fish appears to be covered by numerous white spots. The parasite is easily transmitted from one fish to another. Ich can only be controlled in the free-swimming stage of the parasite. Five to 30 days may be needed before the infestation is completely eradicated.

White to dark nodules under skin - Larval tapeworm (Cestoda)

Black or reddish nodules under skin or in eyes - Metacercaria

Ulcerated patches on skin - Bacterial septicemia or Ichthyophonus

Cloudy skin and gils, blood flecks - pH too extreme

Blisters beneath skin - Gas embolish

Cloudy eyes or blindness - Severe velvet or white spot, metacercaria, toxins

Sunken eyes - Chlorine excess, dropsy

Exophthalmos (pop-eye) - Gas embolism, toxins, copper, some diseases

Lateral line erosion - Lateral line disease (viral?)

Emaciation, paleness, perhaps skin ulcers - Tuberculosis, Nocardia, or Tripanoplasmiasis

Emaciation, paleness, light-colored or bloody feces - Coccidiosis

Emaciation, swollen belly, odd movements - Cestoda (tapeworms)

Red and swollen gills with gray or white spots - Bacterial gill disease

Brown gills - Nitrite poisoning

Eroded or tattered gills - Chlorine poisoning

Gill covers protruding - Gill parasites, goiter, velvet

Swollen body, often scales protruding - Dropsy, intestinal blockage

Scales protruding, body normal - Bacterial infection of scales

Flukes about 1/5", fins perhaps torn - Benedenia

Flukes 1/25" or less on gills or body - Gyrodactylus, etc.

Wood - louse - like crustacea in mouth or on skin - Isopods

Threadworms hanging from anus - Nematodes

Egg-sacs hanging from gills or body - Copepods

Hemorrhages, spinal curvature, pop-eye, cloudy eyes, convolsions (2 or more of these together) - Vitamin deficiency

Behavioral Symptoms

Flashing, fins clamped - Velvet, white spot, toxins

Listlessness, loss of balance - Sleeping sickness, metallic poisoning, chill

Swimming on the spot (Shimmies) - Velvet, chill

Severe loss of balance, belly up - Swim bladder disease

Gasping at surface - Oxygen lack, toxins, gill diseases, tank overheated

Sudden dashes, jumping out of tank - pH wrong, toxins

Unusual colors, especially dark - Toxins, Ichthyophonus

Failure to eat - Stress, wrong food, various diseases

Smears of Skin or Gills

Small flukes - Benedenia larvae, Gyrodactylus, etc.

Pear-shaped flagellate - Velvet (Amyloodinium)

Ciliates:

Ovoid, no hooks - White spot (Cryptocaryon)

Ring of hooks - Trichodina - An external parasite most commonly found in freshwater fish, causing cloudiness on the skin and red areas where hemorrhages have occurred due to the teeth of the parasite.

Heart-shaped or oval, no hooks - Brooklynella or Chilodonella - An external parasite causing the fish to secrete excess mucous, resulting in the appearance of a bluish-white film on the body of the fish. In severe conditions, the skin peels off, gills are damaged and the fish dies. Gills are usually attacted first and symptoms of oxygen starvation are noted.

Single stalked ciliate - Trichophrya, Glossatella, etc.

Branching stalks - Epistylis