Depending on the angle you cast your fishing line you can get the floater to move to strange locations. You can get the floater above or under the water level by 1 or 2 blocks. You will still be able to catch fish and the water particles caused by fishing will still appear on water level.
Steps to Reproduce fishing in mid-air:
1. Grab a Fishing Rod
2. Stand on next to a water source (by default y=63 feet pos.)
3. Cast your line downwards into the water.
Floater will go up and rise above the water level.
Steps to Reproduce fishing underwater:
1. Grab a Fishing Rod.
2. Go about 10-20 blocks deep underwater.
3. Cast your line upwards.
Floater will go up and rise, but it stays about a block under the water level.