Hemiodus is a genus of halftooths from South America with the greatest species richness in the Amazon Basin, but also found in the Orinoco, Essequibo, Paraná–Paraguay and Parnaíba River basins. Depending on the species involved, these elongate fish reach a length of 7–30 cm (3–12 in).

Fossil remains are known from the Middle Miocene-aged Pebas Formation of Peru.

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