Fish and shellfish are nutritionally important foods, yet consumption in many high-income countries remains low and concentrated on a narrow set of environmentally costly species. In the United Kingdom, fish consumption is dominated by a small group of fish—the so-called “Big Five”—which is often treated as an inevitable outcome of supply, convenience and ingrained consumer preferences. However, little empirical evidence exists on how and when such preferences emerged, or whether present-day patterns reflect historical continuity or cultural loss. This limits our ability to interpret current consumer behaviour and to design socially and culturally grounded interventions aimed at diversifying fish consumption. Here, I use published recipes sourced from a British domestic magazine, as a consumer-facing archive, to reconstruct long-term shifts in the cultural visibility of fish. While not a measure of consumption, popular media is widely understood to reflect and reinforce prevailing cultural norms, in this case, assumptions about which fish species were considered available and familiar to domestic cooks. I analyse 1,192 fish and shellfish recipes published between 1923 and 2025, documenting changes in species prominence, diversity, and composition. Sixty-six species were recorded, yet representation became increasingly concentrated over time. From the 1970s onwards, the ‘Big Five’ accounted for more than 60% of all species mentions, coinciding with a statistically significant decline in diversity of species representation and a marked restructuring of species composition. Flatfish, herring, and oysters—once culturally prominent—declined substantially, while salmon, prawns, and tuna became entrenched. Although species richness declined only weakly, diversity fell significantly, indicating increasing homogenisation rather than simple loss of species. These findings demonstrate that contemporary UK fish preferences are historically contingent, shaped by interacting changes in supply, trade, policy, and cultural norms, rather than fixed consumer tastes. By linking supply-side transformations to domestic food cultures, this study reveals how ecological and market changes becomes normalised in everyday consumption. More broadly, it shows how historical perspectives derived from cultural sources can inform strategies to diversify diets, revive under-utilised species, and align future seafood consumption with health and environmental sustainability goals.