Hey Kieran, thanks for the detailed feedback!
As the dev for the game, I do admit the actual fishing experience has a few rough edges. I think I definitely dropped the ball on making it more obvious when fish are about to escape. Each fish has a hidden timer that gives the player `x` seconds to reel the fish in, and also stronger fish will make the player reel it in slower. I think there could've been several ways we visualize this to the player, either making the fish flop more drastically when they're about to escape or make the player's reeling animation look like they're struggling a bit more with the stronger fish.
The point about the space level having more "water" so reaching the fish closer to the bottom is a very valid one, and honestly not something that occurred to me during testing so thanks heaps for that.
This being my first ever game that I've made, I think there was quite a gap between things I considered as being "obvious" (considering I was the sole dev) vs what the player would consider to be obvious. I feel like making the game feel intuitive enough for anyone to pick up on is something I really need to improve on.