Things You'll Need
Air dry clay
Make a replica of a realistic fish skeleton to help you learn about the anatomy of a fish, or a simple one for a macabre decoration. Air-dry clay is easy to work with and you can use a technique to help you bind the fake fish bones together to make a strong clay skeleton. Print out a fish skeleton diagram to help you make a realistic model, or a clip-art image to help you make a simplistic version.
Download a picture of a fish skeleton from the Internet that looks the way you want your fake fish skeleton to look. Print the image on the "Full Page" setting so that prints large. It's okay if the image is blurry or rough around the edges -- you only need the basic shape to guide you.
Mold some white air dry modeling clay into the shapes of the bones and place them on the paper over the image to help you get the right shape of the fish skeleton. Make each no less than 1/4-inch-thick so the clay skeleton is strong. Create the spinal cord and the ribs of the fish this way.
Mix some of the clay with water to make "slip," a gooey substance that helps you "weld" separate pieces of clay together. Attach the bones by cutting tiny slits in the ends where they will join with a knife and applying slip to the ends. Blend the ends of the bones and the slip together where they join. Assemble the bones on the piece paper with the image to help guide you.
Press an eye socket hole in the side of the skull of the fish with your finger and a smaller hole near the front of the skull with the pointed end of a pencil. Blend the edge of the skull to the end of the spine. Make an arrow shape for the tail fin and attach it to the end of the tail the same way. Wait 24 to 48 hours for the clay to dry all the way and display your fake fish skeleton.