What is pacu?

Pacu are omnivorous freshwater fish belonging to the Serrasalmidae family, which also includes piranhas. While they share a family resemblance with piranhas, pacu are generally much less aggressive. Here's some key information:

• Appearance: Pacu are characterized by their robust, deep bodies and powerful jaws. Unlike piranhas' sharp, triangular teeth, pacu possess human-like molars, adapted for crushing nuts, seeds, and fruits. They can grow quite large, with some species reaching over 80cm (30 inches) in length and weighing over 25kg (55lbs). Their coloration varies depending on the species, ranging from silvery-grey to brownish-grey.

• Diet: While they are omnivorous, their diet is predominantly herbivorous. They consume fruits, seeds, nuts, and aquatic plants. They will also consume insects, crustaceans, and occasionally smaller fish, but this is not their primary food source. Their powerful jaws are essential for cracking hard shells.

• Habitat: Pacu are native to South America, inhabiting rivers and lakes of the Amazon and Orinoco basins.

• Behavior: Generally docile compared to piranhas, pacu are still capable of inflicting a painful bite if provoked or handled carelessly. Their human-like teeth have led to several documented incidents of bites, particularly among anglers.

• Popularity as aquarium fish: Smaller pacu species are sometimes kept as aquarium fish, but it's crucial to understand their growth potential. They require large tanks and a specialized diet to thrive, and keeping them in unsuitable conditions is cruel and irresponsible.

• Invasive species: Pacu have been introduced to various parts of the world outside their native range, some through accidental release from aquariums and others deliberate stocking. In some areas, they have become invasive species, outcompeting native fish populations.

In short, while related to piranhas, pacu are mostly herbivores with powerful jaws and human-like teeth. They can grow very large and require significant space if kept in captivity. Their introduction into non-native environments can have significant ecological consequences.