Hydrolycus

{{Short description|Genus of fishes}}

{{Automatic taxobox

| image = Hydrolycus scomberoides by OpenCage.jpg

| image_caption = Hydrolycus scomberoides

| taxon = Hydrolycus

| authority = (J. P. Müller & Troschel, 1844)

}}

Hydrolycus is a genus of large dogtooth characins from tropical South America, where found in the Amazon and Orinoco basins, as well as rivers of the Guianas.{{FishBase genus | genus = Hydrolycus| month = January | year = 2017}} The genus includes the largest dogtooth characins, reaching up to {{convert|1.17|m|ft|abbr=on}} in length. They have long, pointed teeth (shorter and less extreme in H. wallacei) used for spearing their prey, generally smaller fish.{{cite journal |author1=Toledo-Piza, M. |author2=N.A. Menezes |author3=G.M. Santos | year=1999 | title=Revision of the Neotropical fish genus Hydrolycus (Ostariophysi: Characiformes: Cynodontidae) with the description of two new species | journal=Ichthyol. Explor. Freshwaters | volume=10 | issue=3 | pages=255–280 }} In a study of the stomachs of 45 individuals, most were empty, but among the remaining the prey fish were 15–50% of the length Hydrolycus itself.{{cite book | author=Goulding, M | year=1980 | title=The Fishes and the Forest: Explorations in Amazonian Natural History | publisher=University of California Press | pages=185–186 | isbn=0-520-04131-3 }}

In 1999 two new species were described, the first in this genus in 158 years.