Infectious Hematopoietic Necrosis (IHN) is a viral disease that primarily affects fish, particularly salmonids like salmon and trout. It is caused by the Infectious Hematopoietic Necrosis Virus (IHNV), which leads to severe tissue damage in the fish's hematopoietic tissues, affecting blood cell production and overall health. The disease is highly contagious and can spread rapidly in aquaculture settings. Infected fish may show signs such as lethargy, darkening of the skin, and swelling of the abdomen. Effective management practices, including biosecurity measures and monitoring, are essential to prevent outbreaks and protect fish populations.