Predation and starvation are inter-related processes that are considered primary sources of mortality in the early life stages of fish. In this sense, determining the environmental variables affecting the condition of fish larvae is essential to understanding recruitment variability and subsequent success of the adult stock. The present study investigated that variability for the Argentine menhaden (Brevoortia pectinata), the condition of this species’ larvae, is related to El Nino Southern Oscillation (ENSO), local hydrological variability, and food availability. Generalized additive models (GAM) were used to explore the association between the residual condition index (RCI), ENSO, and environmental variables, at monthly and annual scales. ENSO phases did not show significant effects on RCI. In contrast, monthly and annual variability of river discharge, salinity, and chlorophyll a concentration showed significant effects on menhaden larval condition. Optimal values of salinity (20 to 27) and chlorophyll a concentration (10 to 18 μg/l) led to larvae with good body condition in the adjacent coastal zone (ACZ). The RCI of larvae captured in the Patos Lagoon Estuary (PLE) had no significant association with these variables. Larvae with good body condition correlated to river discharge values of below 1000 m3/s and above 2500 m3/s. When river discharge reached values of 1000 to 2000 m3/s, menhaden larvae presented a critical drop in RCI. This study suggests that the variability of local hydrology and its effects on estuarine and coastal productivity are the main factors associated with the body condition variability of menhaden larvae, and suggests hydrology may substantially impact their survival and recruitment.