I don't think so it was there and 30 min later I was taking out rocks and looking on the floor but no signs of the fish. And I haven't herd any clicking at night the tank is in my bed room.
I had a fish go missing too, looked everywhere including the floor. When I moved my 210 last month I found Bicolor Anthia Jerky inside the stand behind the sump. Fish can flip and flop into some pretty interesting places if/when they jump. And I had a canopy on and tops on the back half of the tank to prevent this..
We found a missing yellow watchman goby stuck in the lock line on my wife's 6 gallon jbj! How does a 3 inch goby go through a return pump up the line around a 1/2 in 90 and into 1/2 in lock line. The way we found him was loss of flow and micro bubbles out the little nozzle. I had to take the line off and back flush it to get him out.
Did the rock go back in the tank? I've had two fish dart into a hole in rock, go on a bucket ride, and an hour after being in a new tank swim out like nothing ever happened. I was just lucky that the rocks were placed where it could escape its cave both times.