Aqueous suspensions of fullerene aggregates (aqua-nC60) were used to investigate the movement of carbon-based nanomaterials in a marine water column and to determine their effects on different life stages of a marine teleost. Fullerene aggregates formed precipitates as a result of mixing in natural seawater, and levels of aqua-nC60 were significantly increased in bottom waters after 24 h. Exposure of Fundulus heteroclitus embryos, larvae, and adults to increasing concentrations of aqua-nC60 resulted in very little mortality, and no median lethal concentrations could be calculated at ≤ 10 mg/L. Aggregates of aqua-nC60 did adhere to the chorion but did not affect development of the embryos or their hatching success. Movements of aqua-nC60 through the chorion and into the embryo tended to increase with higher exposure levels; however, the concentrations were extremely low and did not differ significantly. Larvae exposed to increasing concentrations of aqua-nC60 exhibited a significant dose-dependent increase in total glutathione (GSH). This was accompanied by a decreasing trend in lipid peroxidation (LPO), but LPO was not statistically different between treatments. Adult F. heteroclitus exposed to increasing concentrations of aqua-nC60 exhibited an increase in total GSH in liver tissue but not in the gill. No significant effects on LPO were observed in either tissue. Thus, we conclude that aqua-nC60 affects the oxidative stress response of F. heteroclitus and that increased antioxidant defenses provide some physiological tolerance for these materials. Environmental factors influencing uptake, metabolism, and physiological response following exposure, however, need further investigation.