Love the fish animation and the song! I think you set a really clear mood and I think it's really great!
For critiques, I think having the fish use an animation that makes it face left-right-left-right-.... is kinda confusing, especially since you're trying to choose which direction it can jump towards. I think having a slightly milder animation would be nice! Also, I think having walls on the edges of the screen would help as well. It can get a bit frustrating when I land offscreen and I have no idea where my jump is being aimed.
Overall though, this game was super fun so good job! :)