Trespassing on Good Faith (善意のトレスパス, Zen'i no Toresupasu) is the second story of the fifth episode of the anime series, Full Metal Panic? Fumoffu
Summary
As a test of superiority, Sousuke and the karate club's captain compete to care for the injured school janitor; however, their overzealous efforts do more harm than good. The janitor tries to be patient, but finally goes berserk when they accidentally serve his prized pet koi to him for dinner.