The consumption of fish as useful animal protein is on the rise around the world, and the transport of fish is being considered as a means of trade between countries around the world. Every year, the occurrence of the Viral Necrosis Virus (VNN) disease in fish, as their main host, causes great damage to the fisheries industry. Undoubtedly, one of the ways to succeed in the aquaculture industry of the future will be the rapid diagnosis and prevention of aquatic diseases, which are currently the biggest cause of losses in the aquaculture industry. Failure to definitively diagnose the pathogen in aquatic animals has led to an increase in the use of antibiotics and, while it may not lead to definitive treatment, has also led to the development of drug resistance. Therefore, prolonging the time of identification and diagnosis of the pathogen causes more prevalence of the disease, more losses and damages in fish farms and the resulting costs. OIE documents and various pieces of evidence introduce valid tools and methods in the diagnosis of betanodavirus that can be used according to the type of sample and available facilities. In this regard, the selection of a valid and rapid diagnosis method will make a significant contribution to improving methods to control, prevent and combat the spread of this worldwide disease. Therefore, the purpose of this study is to compare different methods of VNN diagnosis and evaluate their advantages and disadvantages.