Acestrorhynchus altus is a species of freshwater ray-finned fish belonging to the family Acestrorhynchidae, the freshwater barracudas. It was described by Naércio Aquino de Menezes in 1969. It inhabits the Amazon River basin, at a pH range of 5.5-7.2. It reaches a maximum standard length of .
A. altus feeds off of bony fish.