Nodavirus is a type of virus that primarily infects marine organisms, particularly affecting fish. It belongs to the family Nodaviridae and is known to cause diseases in various fish species, leading to significant economic losses in aquaculture. The virus can spread rapidly in crowded environments, making it a concern for fish farmers. The most well-known nodavirus is the Betanodavirus, which has been linked to diseases such as viral nervous necrosis (VNN). Symptoms of infection include abnormal swimming behavior and lesions on the brain. Effective management and biosecurity measures are essential to control the spread of nodavirus in fish populations.