Singapore grouper iridovirus (SGIV) was first isolated from diseased cultured groupers in Singapore and has been identified as a novel species within the genus Ranavirus (family Iridoviridae; subfamily Alphairidovirinae). SGIV infection causes considerable morbidity and mortality in many economically important fish species, such as grouper and seabass. In this chapter, we describe virus isolation in cell culture, virion purification, ultrastructural analysis, virion morphogenesis, and molecular identification of SGIV. SGIV has been molecularly characterized based on the SGIV genome, transcriptome, proteome, and viral miRNAs. Various aspects of pathogenesis resulting from SGIV infection were investigated, including cytopathology, virus entry and transport, paraptosis, autophagy, and signaling pathways. Functions of host immune and metabolism-related genes during SGIV infection are evaluated and discussed. Immuno-biological control strategies, including antibody-based flow cytometry and microfluidic chip detection technology, loop-mediated isothermal amplification (LAMP), and nucleic acid aptamer detection methods, were developed. Efficient SGIV vaccines have also been developed. These research approaches provide the basis for a better understanding of the pathogenesis of SGIV and other ranaviruses and offer technical support to control fish ranaviruses.