The Gulf killifish, Fundulus grandis, is one of the largest members of the genus Fundulus; it is capable of growing up to 18 cm in length, whereas the majority of other Fundulus reach a maximum length of 10 cm. Therefore, F. grandis is among the largest minnows preyed upon by many sport fish, such as flounder, speckled trout, and red snapper. Fundulus derives from the Latin meaning "bottom," and grandis means "large". The Gulf killifish is native the Gulf of Mexico from Texas to Florida and the eastern coast of Florida to Cuba in the Atlantic Ocean. Threats to the survival of the Gulf killifish include extreme changes in salinity, changes in temperatures, and toxic events such as the hypoxic dead zone in Louisiana and the Deepwater Horizon oil spill. The Gulf killifish is currently being used to test the effects of oil and oil dispersants on the physiology of marine species affected by these substances. This is significant to conservation biology, because with the continued extraction of oil and other natural resources from North American waters, it has become increasingly important to understand the risks and consequences in worst-case scenarios, such as the Deepwater Horizon oil spill, and the lasting effects on the marine ecosystem.