It seems fossil fish are in the news! Paleontologists have uncovered the oldest shark fossil, which dates back 409 million years. The ancient creature was found at a site in New Brunswick Canada: World's oldest shark fossil found. Additionally, a giant fossilized fish has been discovered by scientists working in Petergorough, England. The giant fish lived 155 million years ago and is estimated to have been 22 meters long: Biggest fish ever found.