The seasonal flooding and drying of the Shark River Slough (SRS) in the Florida Coastal Everglades (FCE) drive a dynamic exchange of energy, as fish prey move out of inundated freshwater marshes and concentrate in mangrove-lined rivers. This pulsing sustains both resident freshwater predators and migratory coastal species, linking food webs across both ecosystems. However, the recent introduction of invasive prey species may disrupt these pathways, altering energy availability and trophic interactions at the freshwater-marine interface. Using stable isotope and gut content analyses, we investigate how freshwater and marine consumers adjust their resource use in response to increases in invasive prey abundance. We also quantify annual total prey energy content represented by communities containing high and low invasive prey abundance and compare these communities to predator diet patterns to assess the impact of invasions on the magnitude of energy flow within and between these linked freshwater and marine systems. Our results suggest that by incorporating invasive prey into their diets, freshwater predators retain a greater portion of marsh-derived production within the freshwater system, potentially limiting its export to marine predators. These shifts in trophic connectivity could have cascading effects on ecosystem stability and resilience. Understanding how invasive species modify energy flow across linked habitats enhances our ability to predict and manage ecological change.