We must be careful about assigning human motives to animals, especially fish. However, whale sharks are known to interact with humans occasionally, and this fellow had a good reason to approach a fishing boat. The shark had a rope caught around its midsection. The fishermen drew the shark close enough to saw the rope loose, and lovingly told the whale shark to take off. I don't know what language they are speaking, but everyone understands "Bye!" including the fish. The whale shark even seems to wave to them as it realizes the rope is gone. But that is speculation, because we must be careful about assigning human motives to animals. At least this fish is free! -via reddit
https://www.radiolab.org/episodes/91701-animal-minds
The part relevant to your post begins at 4:18 and ends about 11 minutes later. You will probably want to ignore the subsequent discussion with someone who says "we can't really understand how animals think..."