Fishy

Fishy is a fish that is the star of Fishy and Friends. He caused Charleyyy to nearly go bankrupt in the events of Bowser's Depression because Charleyyy and Friends was cancelled in favor of Fishy. Bowser hated this, and even tried to commit suicide and fell into a depression. Bowser Junior and Chef Pee Pee tried to cheer Bowser up, and eventually Bowser fell in love with Fishy and Friends. However Fishy's show was cancelled when Charleyyy came back on the air.

Trivia:

 * Fishy's "actor" the goldfish died after the events of Bowser's Depression.