i have a 50 gallon reef tank that has 4 firefish, a blue tang, and other fish. 3 of the firefish are always hiding and only come out for food but if any sudden movements occur they dart back into their hidy-holes. also our blue tang is about 3-4 inches and it is almost ready to go back to the lfs which they said they would take back. what would be the easiest way to catch them without taering the whole tank down? also, the blue tang is extremely fast when nervous