Many specimens once identified as S. porcinum from the Brazilian Amazon Basin and the Venezuelan Orinoco are now known to be a different species, S.

[1] S. porcium is distinguishable from all other Sternarchogiton species by the straight dorsal profile of its laterally compressed head.

The tail is compressed and moderately long, terminating in a small lanceolate caudal fin with 14-22 rays.

The coloration is uniform white on the sides, tinged pink due to underlying capillaries.

The back of the body and head are brown, with white-pink scale margins and white electroreceptor pits.