The name Acestrorhynchidae can be broken down into two ancient Greek words. Akestra means needle and rhyngchos means jaw. A reference to the teeth of this family.
The family is divided into three subfamilies:
In total, the family has seven genera and about 26 species.
Acestrorhynchidae are elongated shaped fish. They all have small scales and are carnivorous. The largest species can reach a total length of about 40 centimetres, the smallest is only 3.5 centimetres long.
The fish of the genus Acestrorhynchus are fish eaters (piscivorous), the other species are more specialized in catching and eating insects and insect larvae.
The species in the Acestrorhynchidae family all come from South America. Most species come from the Amazon and Rio Orinoco. Three species can be found a little further south in, for example, São Francisco. The members of this family are only found in freshwater.