Knights Alta fish fossil specimenKnightia Alta Fish Fossil (from Wyoming): Appearance: The Knightia Alta is an extinct species of freshwater fish preserved as a fossil in shale rock, often with detailed imprints of its body, fins, and scales. The fossil typically shows a sleek, elongated shape with a gentle curve, and the fish often appears to be in a resting or swimming position. The fossil is usually a pale, brownish gray color with intricate details of the fishs form. Size: