Fabien Cousteau, grandson of explorer Jacques Cousteau, is spending 31 days living in the world’s only undersea habitat research lab, Aquarius. Last Thursday, we video chatted with Fabien to ask him about life under water, including how he deals with constant humidity, cramped quarters, and two atmospheres of pressure.

(In the video above, a shark swims past the porthole at 6:43.)

Fabien also gave us a tour of the station, which sits on the ocean floor off the coast of Key Largo, Florida.

You can read about what happens to the human body—physically and psychologically—during a month under the sea in this article by Brian Lam.