Pacu are large, plant-eating relatives of piranha increasingly farmed for food and sold as pets, often with serious welfare consequences due to their size.
Pacu purchased as aquarium fish almost always outgrow their tanks within a year. Most are then either kept in severely undersized conditions — causing skeletal deformities and chronic stress — or released into local waterways, harming ecosystems. In aquaculture, pacu are farmed at high densities that restrict natural foraging behaviour. Their herbivorous nature makes them sensitive to protein-heavy commercial diets. Wild-caught pacu for food face welfare harms from traditional fishing methods common in rural South America.