In Finding Nemo, Bruce is the great white shark who tries to be vegetarian. He belongs to a shark support group that follows the motto “Fish are friends, not food,” alongside Anchor and Chum.
Bruce first meets Marlin and Dory at a gathering held inside a sunken submarine. He presents himself as friendly and committed to avoiding his natural diet, but the arrangement becomes unstable when he smells blood after Marlin accidentally injures Dory. Bruce loses control and begins chasing them, revealing how difficult his self-imposed rule is to maintain.
The character is a comic version of a great white shark, a species known for eating fish, rays, seals, and other marine animals. The film turns that real predator-prey relationship into a joke about recovery groups and self-control.
Bruce is also a small pop-culture reference: his name recalls the nickname of the mechanical shark used during the production of Jaws. Anchor and Chum are fellow sharks in the support group, while Dory is a regal blue tang rather than a shark.