Ponyo

Searching for Gake no Ue no Ponyo? That title and Ponyo point to the same show. Studio Ghibli is the animation studio behind this movie. It's finished airing, so the whole thing is watchable start to finish.

On the shelf it sits under Adventure and Fantasy — worth knowing if you're comparing adventure anime specifically. Looking for something similar? No Game, No Life is the nearest match on the shelf right now.