Cynodontidae, from Ancient Greek κύων (kúōn), meaning "dog", and ὀδούς (odoús), meaning "tooth", also known as dogtooth characins or vampire tetras, are a family of predatory, characiform freshwater fishes from South America. This group is not very diverse, and includes only three genera and eight species. The largest species in this family ranges up to 117 cm (3.84 ft).