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.

Serrasalmus irritans is a species of piranha native to Venezuela and Colombia. It is an abundant top predator in its native range, feeding on fish including fins and scales. No introductions of this species have been reported, and impacts of its introduction remain unknown. History of invasiveness is classified as No Known Nonnative Population. This species is present in the aquarium trade in the United States, although numerous States have prohibited or restricted the trade and possession of this and other piranha species. The Climate match to the contiguous United States was low, however, much of peninsula Florida, the southern tip of Texas, and small areas along the west coast had a medium match. Certainty of assessment is low due to lack of information. Because of the lack of introduction history for S. irritans and the low climate match, the overall risk posed by S. irritans is uncertain.