In the last 2 months I removed a Tomato clown and damsel fish from my DT,each on separate occasions. The first time was for a big 4 inch clown in my 220 gallon XH.I managed to get it after 2 hours,and did not have to move any rock.The floor in the living room got a little wet in a few places,because of all the thrashing around with two nets.But the aquarium was unscathed. Yesterday I removed the oldest fish because he was attacking everything else in the aquarium,a 5 inch damsel....the evil monster...
He lived in a cave in the bottom(or at the base of a huge pile of LR that was 28"tall).I had to dismantle all the LR,to open up the cave, there was no other way to get to him.
I would like to say that because I carefully removed the coral and rock,the extraction of the fish went smoother,than the first time...however,there was still difficulties,but because he was so big he was easy to get once he was out in the open.Removing a fish in a reef is never easy.