Saprolegniasis is a skin infection caused by a microorganism that affects fish whose protective mucus layer has been altered or that are already compromised by disease or stress. Once the epidermis is contaminated, this microorganism, which looks like a fungus, destroys the superficial and deep layers of the skin.
• Causative Pathogen : Saprolegnia parasitica
• Site of infection : Skin, Gills and Eggs
• Species Affected : All freshwater fish species, incubating eggs and other lower aquatic vertebrates/invertebrates.
• Major Pathology :
➢ Skin and gill lesion
➢ Separation and lifting of gill and skin epithelium
• Major Clinical signs :
➢ In severe cases fungal hyphae may penetrate in to dermis and muscle.
➢ No inflammation
➢ No granuloma formation
➢ Lesions on skin appear as cotton wool like focal grey-white patches
➢ Hyphae filaments extend out into the water
➢ External symptoms of bloating due to intestinal blockage in smaller young fish can develop into abdominal wall perforation.
➢ Fish eggs turn white
➢ Fungal attacks always follow some other health problems like parasitic attack, injury or bacterial infection