Pacu (Portuguese pronunciation: [paˈku]) is a common name used in the aquarium trade to refer to several common species of omnivorous South American freshwater fish that are related to the piranha. Pacu and piranha do not have similar teeth, the main difference being jaw alignment; piranha have pointed, razor-sharp teeth in a pronounced underbite, whereas pacu have squarer, straighter teeth, which are uncannily similar to human teeth, and a less severe underbite, or a slight overbite. Additionally, full-grown pacu are much larger than piranha, reaching up to 0.9 m (3.0 ft) and 25 kg (55 lb) in the wild.