Step 1: Cut a small fish shape on a piece of paper. Make sure the fish has a V-shaped cut on its tail.

Step 2: Fill a tray with water.

Step 3: Place the fish in the tray, as shown in the image. Make sure the fish floats. Do not push it underwater.

Step 4: Put a single drop of soap in the water in the cut area.

Now see the fish floating around.