I like the downwards flappy bird idea but it's way too hard at the moment. Since you don't really have control of the fish's horizontal position some times you are just stuck waiting for a gap so you can go through (especially with the anglerfish since they have a very similar speed to your fish) and the parts where multiple fish would cross one after the other without a gap were nearly impossible. Also I found it a bit weird how you can go under the screen if you fall too fast.
I do believe it could be a great mobile game with a bit of polish though!