Just outside of Austin, find endangered species, archeological exhibits and more.. In Short Owned by Texas State University at San Marcos, Aquarena Center lets the public tour the grounds, historic buildings, educational exhibits and aquarium. The large freshwater aquarium brings alligators, Texas wild rice and freshwater eels up close and personal. Individual aquariums feature gambusia, fountain darters and the San Marcos Dwarf Salamander. Aquarena Springs focuses on historical and cultural aspects of the area, as well as the endangered and protected plant and animal life in the San Marcos River.