Acestrorhynchus ("needle jaw" ) is a genus of 14 species of characiform fish found only in fresh water in South America, the sole genus in the family Acestrorhynchidae. Their greatest diversity is in the Orinoco and Amazon basins. These fish have elongated pike-like bodies and large conical teeth, adapted for predation on other types of fish. They are sometimes referred to as freshwater barracudas in the aquarium trade, although the name is used of other characins, as well. They range from 35 to 400 mm in length.