Fossils are essential for understanding the origin of today's environments and biodiversity. Paleontology provides temporal constraints on evolutionary timescales, information about the structure of ancient organisms, and evidence of past geographic and environmental distributions of lineages. Ray-finned fishes, numbering over 30,000 living species, make up roughly half of all living species of backboned animals and have a rich fossil record. However, in comparison to that of their terrestrial cousins, the remarkable paleontological archives available for ray-finned fishes have been little studied. Fossil evidence bears on several key intervals of ray-finned fish evolution, many associated with episodes of profound global change. While textbooks depict a singular "Age of Fishes" in the Devonian more than 350 million years ago, ray-finned fishes have undergone many episodes characterized by anatomical innovations, lineage diversification, or environmental shifts. This talk highlights how diverse evidence from living and fossil species helps us to understand these Ages of Fishes, and in turn the origin of today's familiar aquatic environments and ecosystems.