Dory is the deuteragonist in Disney/Pixar's 2003 animated film Finding Nemo and the titular protagonist in its 2016 sequel. She is a regal blue tang who suffers from short-term memory-loss and is a bit ditzy.
There are roughly one-sh*t billion tropes so PLEASE look through them before adding one. Otherwise add what you like. ADDITION: PLEASE read through the trope description provided before submitting something. It's not a huge deal but too often people submit characters that don't fit just because they misinterpreted the title...