Epizootic Ulcerative Syndrome (EUS) is one of the most destructive diseases amongst fresh and brackish water fish species in the Asia-Pacific region. Almost all species of freshwater and brackish water fishes can be infected but certain important food species such as Mugil cephalus, snakehead and Indian major carps, are particularly more susceptible to EUS. Labeo bata (Bata), a minor carp which has not been previously reported among the species affected by EUS, however recent disease surveillance has shown EUS infections in them. In the present study the infectivity and role of Aphanomyces invadans (primary causative agent of EUS) in the development of ulcerative condition in bata and the effect of such condition on immunological, biochemical, and hematological changes were investigated. Fungus isolation was done from the affected muscle. Histopathological study of muscle and liver tissue from the ulcerated fish was attempted along with the studies on horizontal transmission of EUS among the cohabited fishes.