Unlike most large-scale public aquariums, the Zaragoza Aquarium’s collection is restricted to freshwater species, mostly from rivers. Though there are no sharks or any of the usual impressive giants, the tank’s inhabitants still wow spectators with impressively large freshwater fish, including arapaimas reaching over six feet long. The Zaragoza is Europe’s largest freshwater aquarium, featuring species from five continents, and representing some of the world’s most prominent river ecosystems, including the Nile, the Mekong, the Amazon, the Darling Murray, and the Ebro. Beyond fish, the tanks are home to various creatures,…