The key to it is to allow it to stay in the tank a day or two if possible so they can adjust to the new "cave". Once they are comfortable with it, and the fish you wish to remove is near it, place the fish between the net and the pot. The fish will go to the pot every time, then it's easy to set the pot upright and remove both the pot and fish. My GSP's rarely swam up and out, usually they would sit near the bottom of the pot.