Gyotaku

Gyotaku is a traditional form of Japanese fish printing or rubbing, dating from the mid-19th century, a form of nature printing used by fishermen to record their catches. In order to make a gyotaku print, one places the subject (e.g.fish, crab, scallop shell) on a wooden bench and paints one side with sumi ink. Next a piece of paper or other material is laid over the ink-covered fish. Finally, one rubs the material until there is the image of the fish on it. Modern gyotaku artists often substitute acrylic or other painting material for the traditional sumi-e.
Gyotaku is also practiced as a form of art, and is very popular among young children both in Japan and Western countries. Sometimes, rubber fish replicas are used. Source Wikipedia