Catch quote
From Nookipedia, the Animal Crossing wiki
A capture phrase is the phrase the player uses upon capturing a fish or bug. It begins with "I caught a [blank]", followed by a comment, often a pun or some other kind of joke. For example, when the player captures a Sea Bass in Animal Crossing, the player will say "I caught a sea bass! See? Bass! (Why do I keep saying things like that?)".
The capture phrase for a particular species changes from game to game, although the joke may be used again.