Fish get stuck on the boat. It does not affect fishing, however, it is bothersome to see.
It's happened to me on levels 17, 18 and 19. And, yes it is bothersome and distracting.
Yesterday I had snagged a shark ray , which I need, and i ended up after a snap in my friends boat....I had to leave the party to have the fish disappear...it didn't register on my list at all...