Fish swiming through coral...
 

I saw the Rock Beauty Angel swim right through the top right coral rock above cave.

Kind of looked like a ghost, his head peaked out through the rock facing the screen and his tail was still on the other side of it.

Then he just swam through and came out in front of it.

Again - don't bother reporting pass-throughs until I have a chance to redo the collision- avoidance code.