In this study, we molecularly characterized and studied the gene expression patterns of three SOD isoforms (Cu/Zn-cytosolic SOD, Mn-mitochondrial SOD, and Cu/Zn-extracellular SOD) regarding their antioxidant defense roles associated with development, ontogeny, and infection in the Siberian sturgeon A. baerii, the extant primitive fish that occupy the basal phylogenetic position (Chondrostei) of the ray-finned fish group (Actinopterygii). Here, SOD1 is linked to infection.