I would like to report a bug not sure if it supposed to be one but every time I close the game and relaunch it the fish in your inventory goes away. Had to test it if it was a fact or I was forgetting that I was selling so I caught 3 fish and saved then close the game to relaunch and then they were just gone.
Known bug (I think); The amount of fish you have is actually shared between every save you have. This is probably caused by the fish counters being static counters (shared) instead of being local counters (save-specific). Consequently, by being static, the fish counter will reset every time you reload the game, no matter what.