The fish were on cardstock type of paper. I got them at the party store. They were flat and very colorful - both sides, so they could face either direction. I hung them with sticker type things that you hang pictures up with (maybe Scotch brand?). It was about 2 inches long and 1/2 inch wide. The package said it didn't hurt the paint, etc. We had no problems with it. In the past I tried masking tape and it kept falling down.