I was diving on Grand Cayman the past 2 weeks. Silversides where in caverns there.
The silversides part and reform behind you so its like swimming in a bubble that is moving and the walls of the bubble are fish.
Here is one video of it. Stay to the end as the second half is better than the first. No color correction, all natural lighting so at this depth (50ft) all reds are gone and mostly the world is shades of silver and blue.
No editing, no music, just a 1 min video so give an idea fo what it was like - straight out of the camera.
I stayed with them for about one hour one day then came back for another hour another day.
I will post some pics and a trip repot shortly. Just back and wanted to share something now.