Maize has antioxidant properties and a high amount of carbohydrates, while fish has high-quality proteins and unsaturated fatty acids. The goal of this study was to prepare a functional food enriched with protein and n-3 fatty acids from Scomber scombrus. A sensory analysis was carried out, along with a texture profile, color and proximate analyses, content of EPA+DHA, and shelf life analyses on five formulations of the snack produced. The best-accepted formula turned out to be the one containing 15% fish, and in comparison with the control, it displayed similar fracturability, less hardness, a higher amount of protein and lipids, and EPA+DHA (p ≤ 0.05), providing 14.6% of the daily recommended intake of EPA+DHA (30 g of product). The development of new products, such as the one proposed in this study, can be a new and healthy alternative to substitute other similar, commercially sold products with a lower amount of nutrients.