Place the LR with the stars in the display for a day or 2. Many, if
not most, will move off in search of space that hasn't been picked
clean of food. You can then put the rock back in the fuge.

Sorry I probably should have been more clear - they are in the rock,
not on it, and are unlikely to leave unless REALLY hungry or they
outgrow the rock. I'm guessing they filter feed too. There's certainly
less detritus in the fuge than the display, and they haven't left their
rock.


Stu