My three bar gobies sleep under the same piece of LR
dug in the sand.
The tang sleeps behind the pile of rocks on the right side against the wall and rocks.
Sixline seems to weave in and out of the rock all the time.
The snails all dig in under the sand bed and go to sleep. They all pop up when I throw in food.
Finally.. the weirdest of mine.
The maroon clownfish sleeps vertically, head up top and tail towards sand in the right corner of the tank.
All these fish sleep in the same place every night.