A crossover episode of Phineas and Ferb and Fish Hooks. Phineas and Ferb shrink down to microscopic size and visit Milo, Ba, and Oscar's tank, where they try to make a business deal with the fishy friends. Meanwhile, Perry goes to fight Doofenshmirtz and Norm with his new Robotinator, but the platypus agent soon worries that his owners are replacing him with fish.