The pelagic Gulf evokes imagery of sunlit blue waters filled with fast-swimming fishes. Yet during the night billions of mesopelagic animals migrate to the upper layers of the Gulf. The change in sunlight from day to night is a well understood and quantified driver of the migration of mesopelagic animals from deep waters at day to surface waters at night, a phenomenon known as diel vertical migration (DVM). However, mesopelagic animals do not always migrate at night suggesting a different driver for nighttime migration. An extensive dataset developed in the Gulf was used to provide a case study of nighttime pelagic dynamics. In the north Atlantic, the lanternfish Hygophum taaningi (Myctophidae) is reported to undertake lunar vertical migration (LVM), defined as migration during specific moon phases. Taking nighttime conditions one step further, we assess the effectiveness of modeled moon phase and moonlight to predict the vertical distribution and abundance of H. taaningi in the Gulf. Generalized additive models were used to investigate the relationship between H. taaningi abundance, moon phase, and moonlight from the surface to 1000 m. Results demonstrated LVM behavior in the open Gulf, with a strong response to both moon phase and moonlight in deeper mesopelagic models, and marginal responses to moon phase in epipelagic models. Overall, H. taaningi was found in deeper mesopelagic waters during new moon and crescent phases, with upward migration to epipelagic waters during half-moon through full moon phases. As global interest regarding mesopelagic fishes (especially the Myctophidae) grows, there is a greater need for accuracy in quantifying fish distributions and abundances. The LVM pattern demonstrated here for H. taaningi is unique from other LVM patterns found in ataxonomic studies and studies that focus on different species, indicating that improvement of pelagic ecosystem modelling requires more knowledge of species-specific vertical distribution patterns.