Fungal diseases of fish

Saprolegniasis (Water mold disease)

• Causative agent is Saprolegnia parasitica
• Develops in injured, weakened, diseased or dead fish.
• External lesions open the way for the disease pathogen.

Disease symptoms

• Characterized by wooly, whitish or lightly brown blotches on the skin, fins, eyes, mouth, gills or on unfertilized eggs too.
• First indication is dullness of body color.
• Ulceration of skin, exposure of jaw bones, blindness, inflammation of liver and intestine
• Infected fish rub their body against hard surface due to irritation.
• Fish shows abnormal movement.

Control measures

• Treat primary injuries of fish.
• Use 1:10 solution of iodine or 1% potassium dichromate for cleaning affected part.
• Dip diseased fish in 0.3% common salt solution or 1:2000 solution of CuSO₄ or in 1:1000 KMnO₄ solution for 5-10 minutes .
• Treat fertilized eggs with 3-4% formalin or 1-5% salt for 10 minutes.
• Treat infected eggs in incubation tank with malachite green @ 5g/L.