Paddlefish are back on exhibit, and you can visit these fish in the newly renovated Charles and Marjorie Schrup Family Foundation Upper Mississippi River Pool aquarium. These ancient filter feeders have been swimming in our waters for over 200 million years. They’re largely unchanged since the days of the dinosaurs. These fascinating fish use their long nose, called a rostrum, to detect prey such as aquatic invertebrates, including zooplankton, mayflies, Daphnia (water fleas), and the larval for