You may not get a lot of activity from this fish. It really has no reason to move. It is waiting to see something move in front of it. Try putting a small live earthworm underneath its nose. Your fish does not look thin. Be patient and allow the fish to settle in. Sometimes it takes a week, sometimes a month. If you are really wondering if it moves, throw in half a dozen rosy reds right after you turn out the lights and check in the morning. Regardless, this is an ambush hunter and will remain still for much of the time.