Slender Pacu

Acnodon oligacanthus has been confirmed to occur in the Maroni and Mana rivers in French Guiana and in the Maronwijne and Suriname rivers. Its presence in Amapá, Brazil and Guyana have still to be confirmed.

Acnodon oligacanthus is the type species of the genus Acnodon, a name which prefixes a-, meaning without, onto knodon, which means "the projecting teeth on a hunting spear", an allusion to the mistaken perception that this species does not have a spine in front of its dorsal fin, it actually does, but it is very small. The Specific name oligacanthus, combines the Greek lígos, meaning "little", "small" or "few", with ákantha, meaning "thorn", alluding to the small and difficult to discern spine to the front of the origin of the dorsal fin.