The bug

Sometimes when a fish is punched or pushed out of water from a high place, they will attempt to float through the air back to the water.

How to reproduce

1. Place water on the edge of a cliff, with the side facing the cliff exposed to any non-solid block.
2. Spawn a fish in the water.
3. Punch the fish out of the water and over the edge.
4.  The fish may attempt (or succeed) to float back to the water _{^{(hilarity ensues)}}.