The Fluvarium, a glass-sided cross-section of a 'living' river, is located across the street from the CA Pippy Park's campground. Viewers can peer through large windows to observe the undisturbed goings-on beneath the surface of Nagle's Hill Brook. Numerous brown trout and the occasional eel can be seen. There's also a demonstration fish hatchery.

If there has been substantial rain or high winds, all visible life is lost in the murkiness.