Due to its numerous health benefits, fish consumption should be strongly encouraged. Fish consumption, however, is a complex phenomenon influenced by various factors. The aim of this research is to examine the influence of knowledge, product information, and satisfaction with product attributes on fish consumption in a nationally representative sample of people responsible for food purchasing within households in Croatia (n = 977) and Italy (n = 967). Fish consumption was well predicted (R2 = 15%) by the proposed structural model, using the partial least squares structural equation modelling method (PLS-SEM). The obtained results confirm that subjective knowledge (β = 0.277, p < 0.001) and satisfaction with product attributes (β = 0.197, p < 0.001) are predictors of fish consumption. Subjective knowledge was influenced by product information (β = 0.161, p < 0.001), as well as by satisfaction with product attributes (β = 0.282, p < 0.001), while objective knowledge had an influence on product information (β = 0.194, p < 0.001). Although satisfaction with product attributes was the strongest predictor of subjective knowledge in both countries (βCRO = 0.244, βIT = 0.398), it had a greater effect among Italians (p = 0.001), while the impact of product information (βCRO = 0.210, βIT = 0.086) was more pronounced among Croatians (p = 0.010). Since the mediating role of subjective knowledge in all models was confirmed, action focused on enhancing subjective knowledge should be taken to increase fish consumption.