The "Jaguar Cove" exhibit at Seattle's Woodland Park Zoo does indeed have underwater viewing, although the two jaguars (which rotate in the enclosure) are noteworthy for rarely ever going into the wet stuff. Occasionally food is tied to plants hanging over the water to entice one of the cats to venture in. One of the jaguars had never seen such deep water before and originally the water was drained to a few inches before gradually being filled up again.
The underwater viewing of the malayan tapirs at the Taronga Zoo is very well done, and that exhibit is still basically brand new.
The underwater viewing of the malayan tapirs at the Taronga Zoo is very well done, and that exhibit is still basically brand new.