I used this general template, which should fit a standard Zippo. You can trace it or , as I did, print it on the back of your vinyl sheets. You need to cut two large strips of white, two zigzags of red to make teeth and the smaller strips of black for the edges and eyes/ gills. You can use scissors but a scalpel or craft knife is best.
The black template is a rough guide you may want to make it thicker if you are having trouble cutting it out.