Fish that live in the twilight zone region of the ocean are a crucial part of a vastly under-studied ecosystem. When fish are brought up to the surface for study, the change in pressure between their native depth (200-500 feet) and sea level often causes fatal damages to their anatomy. Watch how a team of scientists from the California Academy of Sciences designs and builds a portable chamber that creates a pressure-controlled environment for these animals, so they can safely transport them from the twilight zone to the aquarium. This video is part of our Engineering Is: Bringing Fish Up from the Deep e-book. The e-book explores the science and engineering principles behind the California Academy of Sciences’ portable decompression chamber, and includes videos, interactives and media making opportunities. You can find our other e-books at kqed.org/ebooks.