Infectious Salmon Anaemia Virus (ISAV) is a virus that primarily affects farmed Atlantic salmon. It causes a serious disease known as Infectious Salmon Anaemia (ISA), which can lead to significant fish mortality and economic losses in aquaculture. The virus is highly contagious and can spread rapidly among fish populations, especially in crowded farming conditions. ISAV is an enveloped RNA virus belonging to the Orthomyxoviridae family. Infected fish may show symptoms such as lethargy, anemia, and hemorrhaging. Effective management practices, including biosecurity measures and vaccination, are essential to control the spread of ISA in fish farms.