In Scottsdale, Ariz., the Phoenix suburb that describes itself as “The West’s Most Western Town,” a new attraction is in the works. But it’s not what you might expect for a city known for its cactus-meets-cowboy chic.

Construction has begun on OdySea, a 200,000-square-foot, two-million-gallon aquarium that is to open in July 2016. Displays will include a room showcasing 500 phosphorescent flashlight fish, a floor-to-ceiling view of the shark tank from the bathrooms and escalators in tunnels, “so you’re actually traveling through large aquariums as you make the journey to the bottom of the oceans,” said the lead developer, Amram Knishinsky.

Visitors age 8 and older can even walk on the floor of the aquarium, he said, using Sea TREK helmets to dive underwater without needing a Scuba certification.

A version of this article appears in print on May 3, 2015, on page TR3 of the New York edition. ||