Cell cultures are employed in diverse research fields such as virology, physiology, toxicology, immunology, oncology, genetics, and pharmacology. These systems can be utilized for pathogen detection, confirmation, and characterization especially of viruses. It is also applicable in the case of i ntracellular bacteria, myxosporean or microsporean parasites. Fish cell cultures have gained more popularity in recent years and have prominent roles in viral disease diagnosis. Since treatment options are limited in the case of several viral diseases, early disease diagnosis and prophylactic measures are key for successful fish health management. Propagation of fish viruses in vitro using cell cultures is imperative in advancing research on viruses and to facilitate disease management strategies such as vaccines and antiviral agents. Moreover, potential host range of pathogens via cell culture susceptibility, virus-host cell interactions, and virus localization studies using cell cultures provide a better understanding of the viral pathogenesis. Availability of appropriate or host-specific fish cell cultures for propagation of viruses and disease diagnosis is very limited, which is a major concern in this area. The wide array of applications exemplifies the versatility, cost-effectiveness, and high potential of fish cell cultures in various research fields. The recent swift growth observed in research employing cell cultures is definitely an outcome of the progress in this sector and also due to increasing ethical demands for reduction in the use and replacement of animals in research. In near future, innovations in 3D cell culture and CRISPER-Cas9 genome editing will further enhance the research prospects of fish cell cultures.