Catfish Disease

The pathogen that causes disease is usually always present in the environment, as is the host (fish). It is only when a stress of the environment overlaps these two variables that disease onset occurs. For farmed fish, stress is always present and can be caused by overcrowding, handling etc. But most disease onset occurs during the drastic temperature change from winter to spring and from fall to winter.

If disease is detected early enough, most problems can be easily and speedily resolved.

Warning Signs of Disease:

Physical Signs:

• Blistered Areas
• Swollen bellies
• Popped-out eyes
• Bloody (hemorrhaged) areas on fins
• Discoloration or erosion of body parts
• Excessive mucus
• Growths on the body

Behavioral Signs:

• Failure to feed properly
• Flashing (turning on their sides)
• Rubbing on the bottom
• Gathering around the water inflow
• Reduced vitality
• Gasping at the surface

In most of the diseases- the physical observatory symptoms are similar. A better detection method is needed in order to prevent outbreaks.

Enteric Septicemia of Catfish (ESC):

• Industry estimates indicate that ESC has been the most important disease on 70 percent of catfish farms during the past 3 years
• Caused by gram negative bacterium Edwardsiella ictalluri
• ESC usually occurs in a temperature range of 22o-28o C (indicating seasonal temperature changes)

Catfish infected with ESC can often be seen swimming in tight circles due to the presence of the bacteria within the brain. Infected fish can also sometimes be seen vertically aligned in the water column and cease feeding immediately after infection.

External symptoms of ESC in farm raised catfish can sometimes but not always include:

• red or white ulcers on surface of skin
• pinpoint red spots under the head or on ventral (belly) region
• Red-raised ‘pimples’ between the eyes
• Swollen abdomen

Internal symptoms of ESC in farm raised catfish can sometimes but not always include:

• clear or yellowish fluid in the body cavity
• liver is spotted with pale areas of tissue destruction (necrosis)
• Intestine filled with bloody fluid