From the aquarium where the otters were active and close.
And in the underwater room where you have to trust the power of glass between you and the water all around you, including above, we sat and watched the sturgeon.
From the World Wildlife Fund site:
One of the oldest families of bony fish in existence, they are native to subtropical, temperate and sub-Arctic rivers, lakes and coastlines of Eurasia and North America. They are distinctive for their elongated bodies, lack of scales, and occasional great size: Sturgeons ranging from 7–12 feet (2-3½ m) in length are common, and some species grow up to 18 feet (5.5 m). Most sturgeons are anadromous bottom-feeders, spawning upstream and feeding in river deltas and estuaries. While some are entirely freshwater, very few venture into the open ocean beyond near coastal areas.
A threatened species
Some species of sturgeon are harvested for their roe, which is made into caviar. The late sexual maturity of sturgeon (6-25 years) makes them more vulnerable to overfishing. It is estimated that the number of sturgeon in major basins has declined by 70% over the last century. During the 1990s, the total catch was dramatically increased by unprecedented illegal harvest. Poaching activity in the Volga-Caspian basin alone is estimated to be 10-12 times over the legal limits. Further problems are caused by water pollution, damming, destruction and fragmentation of natural watercourses and habitats which affects migration routes and feeding and breeding grounds.