Ecological forecasting provides a framework for evaluating ecosystem restoration by simulating alternative management scenarios and predicting their ecological consequences. In wetlands, restoration efforts have focused on hydroperiods, but recent studies have shown that water flow has been an overlooked driver of nutrient availability and consumer production. Yet, the ability of flow to predict consequences of management changes has never been assessed. The Florida Everglades is a managed ecosystem that is undergoing the largest restoration project in the world. Current objectives of Everglades restoration include increasing wet season discharges across the southern portion of the ecosystem to match historic wet-season water velocities (2–5 cm/s). One indicator of restoration success is the production of small fish and crayfish that are the preferred prey items of wading bird populations in south Florida. We used a long-term monitoring data set (2018–2025) to model the densities of total fish and the two of the most common species in Everglades National Park (Bluefin Killifish, Least Killifish) using antecedent hydrological covariates. We used a cross-validation procedure with a least absolute shrinkage and selection operator (LASSO) regression to compare the change in fish density predictive performance (mean squared error) when including discharge to a baseline hydrologic model. Including discharge reduced mean-squared error by 8 – 10% for all fish density response variables and discharge had a positive effect in all cases. Using the final LASSO model that included discharge, we predicted fish densities to a simulated baseline hydrologic scenario and two restoration scenarios. The two restoration scenarios we assessed differed by the spatial extent of an underground seepage wall along the eastern boundary of ecosystem (including Everglades National Park [ENP]). We calculated the relative change in fish density between the baseline scenario and the two restoration scenarios. Both restoration scenarios increased discharges in ENP by 20 – 50 %, resulting in similar relative increases in total fish density and density of Least Killifish and Bluefin Killifish. These findings show that discharge is a critical variable for predicting responses in fish density and that further flow restoration is expected to benefit fish production.