The Fairly OddParents (2001)

S5E27 Smart Attack

Timmy's dad is eager to assist him with his homework, but his well-meaning efforts only complicate things. Timmy wishes for a smarter dad to make things easier, and suddenly, Dad transforms into a genius. He starts homeschooling Timmy and begins to focus obsessively on Timmy’s neglected goldfish. After years of neglecting to feed them, Dad decides they must be a unique species and plans to dissect them in front of the scientific community, unaware of the chaos he’s about to unleash. Timmy now has to navigate the fallout from his wish without hurting his dad's feelings.