This study utilized th e AC Nielsen retail scanner data to present a comprehensive analysis of substitution patterns among various finfish products in the U.S. retail market. A weekly scanner data spanning 260 weeks from Sep tember 2016 to August 2021 was employed for this work. Previous studies have identified frozen and refrigerated fillets as the most common seafood products for major species such as s almon, tilapia, catfish, swai, and trout. We employed a non-linear Almost Ideal Demand System (AIDS) model for assessing the elasticity of demand and identifying substitution and complementarity relationships between these five major seafood categories. The detailed implications of these trends, revealing both complementarity and substitutability among the finfish categories, will be further explored in our presentation. The findings are critical for domestic aquaculture stakeholders as they help them position their products relative to other similar finfish products