I have done this in my 135, move all items out of one end about 2', use a piece of egg crate as a divider, heard the fish to open area set up divider (good idea to have divider in tank ready to stand up use suction cups to hold in place). Now the fish is in smaller area with nothing to hide in. Also here is my advice on fish catcher. Take a 2 quart water bottle with handle (ribs on bottom is helpful) cut off top and bottom sand edges attache plastic bag with rubber bands to ribbed side, then heard fish into bag with net. Good luck