Abnormal Behavior and Cause Analysis of Sick Discus Fish

For a generally sick discus fish, we can roughly understand its possible causes from abnormal behavior, appearance, and so on.

Abnormal behaviors of sick fish and their causes:

1. The fish floats to the water surface, moves sluggishly, and looks listless -- oxygen deficiency, gill parasites, and bacterial infection.

2. Feeding rate decreases -- water quality may have deteriorated.

3. Gathers in one corner at the bottom of the tank, clamps its fins, etc. -- may have internal or external parasites, bacterial infection, etc.

4. Rubs against the tank wall or heater tube -- external parasite infection.

5. Convulsions -- caused by internal or external parasite infection, or poor water quality and incorrect pH value.

6. Hangs upside down, head down and tail up, loses balance -- brain infection, inflammation of the swim bladder or kidneys.

7. Gill covers open, breathing rapid -- gill parasites and bacterial infection.

Appearance symptoms and possible causes:

1. Body color darkens -- intestinal and bone discomfort or indigestion; gill parasites, external parasites, internal parasites, and viral infection.

2. Fish body becomes emaciated -- hexamitiasis, capillariasis, tapeworm disease, and tuberculosis.

3. Abdomen enlarges -- parasitic disease and bacterial inflammation, or food spoilage bloating disease.

4. Fin damage and erosion -- costiasis, bacterial fin disease.

5. Eyes dark black -- internal parasites, internal inflammation.

6. Exophthalmos (bulging eyes) -- caused by nephritis, tuberculosis, and parasitism by the diplostomulum of the genus Cylindrocaululum.