The formation of biogenic amines (BAs) in fish products during storage forms a serious challenge to producers and is generally related to the growth of decarboxylase-producing microorganisms. Controlling the formation of BAs is a serious challenge for the fishery industry. This study evaluates the impact of incorporating molecular hydrogen (H-2) in a modified atmosphere packaging on the formation of BAs in both freshwater and seawater fish, i.e., rainbow trout and horse mackerel, respectively, stored at + 4 degrees C for 15 days. Fish samples were packaged in modified atmosphere packaging [MAP1 (50% CO2/50% N-2) and MAP2 (60% CO2/40% N-2)], reducing atmosphere packaging [RAP1 (50% CO2/46% N-2/4% H-2) and RAP2 (60% CO2/36% N-2/4% H-2)], and under air (control). The amount of BAs, except spermidine and spermine, significantly increased during storage in all treated samples. Both MAPs and RAPs showed significant restrictive effects on the formation of heterocyclic, aromatic, and aliphatic di-amines (histamine, tyramine, putrescine, cadaverine) in both fish species, with a more potent effect seen in RAP rather than MAP. Reduction rates of BAs Pwere about two folds higher in RAPs than that of MAPs. This shows the advantage of hydrogen incorporation in the package atmosphere on the inhibition of biogenic amine formation, especially in the presence of a high level of CO2. Therefore, RAP may be proposed as a promising technology for limiting the BA formation in fishery products.