In the game Animal Crossing there are a couple of octopus characters. I have one of them living in my town now. Marina, sweet gal. Funny to see a cephalopod bat her eyelashes at you.
Anyway, I'm guessing the friendly octopi are a sign of the game's Japanese roots. I've seen other examples in manga and advertising cartoons. (Not getting into Dream of the Fisherman's Wife right now.) It would seem to predate The Little Mermaid by quite a bit too.
I guess if you live on an island in the middle of tropical storm country, you'd best get to know and love the things of the sea.