They are known as Saprolegniasis, Branchiomycosis, and Ichthyophonus disease. Branchiomyces sanguinis and Branchiomyces demigrans . Branchiomycosis is a pervasive problem in Europe, but has been only occasionally reported by U.S. fish farms. The main sources of infection are the fungal spores carried in the water and detritus on pond bottoms. Disease Signs Branchiomyces sanguinis and B. demigrans infect the gill tissue of fish.
Gills appear striated or marbled with the pale areas representing infected and dying tissue.
Gills should be examined under a microscope by a trained diagnostician for verification of the disease. Damaged gill tissue with fungal hyphae and spores will be present. As the tissue dies and falls off, the spores are released into the water and transmitted to other fish. High mortalities are often associated with this infection. Management and Control Avoidance is the best control for Branchiomycosis.