Species that are considered uncertain risk need a more in-depth assessment beyond the Risk Summary to better define the species’ risk to U.S. environments.
P. mexicana is a freshwater fish native to Mexico and Central America. It is reported from and established in several western U.S. States, and it is present in the aquarium trade in the United States. History of invasiveness was classified as “None Documented” for P. mexicana because research on introduced populations of the species has failed to directly link P. mexicana with negative impacts on native species. Nevertheless, several authors argue that introduced P. mexicana has been involved in the decline of certain native species in the western contiguous United States and Hawaii through mechanisms of competition, predation, and parasite introduction. P. mexicana has a high climate match with the contiguous United States, especially in areas of the country where it is already established in the wild. Overall risk assessment category is uncertain.