Gery's Piranha reaches sizes up to 12 inches in length.

As of 2018, it is classified as Least Concern by the International Union for Conservation of Nature.

The fish is distinctive at all ages, possessing a broad dark stripe running from the lower mouth to the top of the beginning of the dorsal fin.

The body is silver with numerous small spots on the flanks.

The anal fin is hyaline with a broad black margin.