Opportunistic records, especially for rare species, are often the first available data revealing geographic expansions in a context of global change in marine ecosystems. On the basis of a first record in the north of the North Sea of the mesopelagic fish Diretmichthys parini (Post and Quéro, 1981), initially described as tropical and subtropical, a hypothesis of geographical expansion in relation to global warming was formulated in 2017. The analysis of a larger set of spatial and temporal data, including historical (1992-2016) records from Iceland and recent (2017-2021) records from Norway, induces a revision of this hypothesis and makes it possible to reconsider the thermal preferences of the adults of this species. The new importance of social media as a tool to monitor records is also highlighted, as pictures of unusual fishes are frequently being posted there.