I really like more creative games with bolder moves and this one is very relaxing. I really like the visual and the music, they are simple, but they do the trick.
Physic colliders are a bit crude (it kills the pace a little, at the end of 2 minutes for example) maybe using smaller colliders even if sprites are a bit overlaping will make fishs more fluid.
I would love to see other types of fish and maybe an adaptative audio based on how many and what type of fish is following you, would be great!