<p>Neglected and underutilized fish (NUF) is proposed as a concept inspired by neglected and underutilized crop species (NUS) in agriculture, directing attention to fish species that are discarded or insufficiently utilized despite being landed. To document the status and emerging trends of NUF in Japan, information was gathered from two complementary sources: nine fieldwork surveys in three fishing villages (Ito, Owase, and Ofunato) and explanations extracted from newspaper articles. The analysis shows that NUF arise from declining market value and structural constraints in distribution, shaped by consumer preferences, species homogenization, and increasing market concentration. Recent public attention to NUF reflects both heightened social awareness and deeper socioeconomic transformations in fisheries, including demographic shifts, changing consumption habits, and loss of local processing capacity. To clarify classification, a two-criterion framework based on end use and market value is proposed. The findings highlight the need to promote alternative value chains, encourage diversified utilization, and ensure sustainability. The concept of NUF provides a foundation for further empirical research and offers implications for fisheries management, food system resilience, and policy development.</p>