Copper is a common xenobiotic that has been shown to cause oxidative stress in fishes via contamination through the environment. Oxidative stress occurs when there is an imbalance between antioxidants and reactive oxygen species (ROS), which can result in an overall reduction in fitness. Glutathione (GSH) and superoxide dismutase (SOD) were the two antioxidants measured to determine if exposure to copper contamination at 11.1 µg/L in freshwater, the Environmental Protection Agency's (EPA) Water Quality Criterion (WQC), would result in sub-lethal effects in exposed sailfin mollies (Poecilia latipinna), compared to a control. The sailfin molly is a euryhaline fish of strong ecological importance, given it's wide range from North Carolina down and throughout the Yucatan Peninsula. After an acute exposure of 96 hours, the mollies were dissected and their tissues put through protein assays. The results show that there is no significant difference between exposed fish and control (t-test; GSH liver; GSH brain ; SOD liver ; SOD brain -value= 0.4081), nor between males and females (one-way ANOVA; GSH liver -value= 0.6346; GSH brain -value= 0. 5317; SOD liver -value= 0. 4423; SOD brain -value=0. 8776). The WQC used to expose the sailfin mollies is significantly lower than what has been found in the environment, and so may not cause the sub-lethal effects that environmental concentration have shown.
