Twilight Zone: Deep Reefs Revealed

Life in technicolor: Neon-hued fish and corals abound in Twilight Zone’s vivid habitats.
To the extreme: See what it takes for our scientific divers to safely reach mesophotic depths.
Elusive oddities: Encounter fish species rarely on public view, including peppermint angelfish.
Spineless and stunning: Flowery tube worms and fluorescent corals showcase the diversity of mesophotic invertebrates.

Descend into a mysterious, little-known ocean realm where vibrant creatures illuminate the shadows, exploration requires advanced equipment, and Academy scientists make remarkable discoveries on every dive.

Prepare to cross over into the Twilight Zone, a newly refreshed exhibit in Steinhart Aquarium that unveils the dazzling marine life inhabiting mesophotic reefs 100 to 500 feet below the surface. Intrepid explorers will encounter an ocean of surprises throughout the exhibit, including:

New-to-science and rarely exhibited animal species
Cutting-edge diving gear and technology
Inspiring insights into Academy research

Plunge into these uncharted waters alongside Academy scientists as they uncover the secrets of these unique ecosystems—and work to protect them from intensifying environmental threats.

A rose-veiled fairy wrasse in shades of purple and magenta against a dark background.

Captivating creatures

Meet a colorful cast of dozens of deep-dwelling fish and invertebrates, including candy-colored anthias, otherworldly corals, and a damselfish so recently discovered it doesn’t yet have a name. Play our Twilight Zone Explorer game to see if you can safely collect specimens at depth.

^{Rose-veiled fairy wrasse}^{photo: © Yi-Kai Tea}

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A child touches an interactive display in the Twilight Zone exhibit at Cal Academy

Under pressure

With hundreds of feet of water above them, divers in the twilight zone are under intense pressure—literally. To descend to such depths, divers must undergo extensive training and use high-tech equipment like closed-circuit “rebreathers,” which allow them to extend their research time underwater. Speak into our dive communication box to hear how your voice would sound hundreds of feet below.

Fluorescent coral glows neon green in the Twilight Zone exhibit at Cal Academy

Go with the glow

From fluorescent corals and anemones to bioluminescent flashlight fish, animals in the twilight zone use specialized strategies to communicate, feed, and reproduce in the dark. Run your hand along our interactive LED wall and flutter your feet as you walk to stir up some simulated bioluminescence.

^{Candy cane coral photo: J. Charles Delbeek © California Academy of Sciences}

Underwater photo of Steinhart Aquarium Director Bart Shepherd using a decompression device to safely bring a mesophotic fish up to the surface

In-depth research

Academy scientists and researchers have led first-of-their-kind expeditions in twilight zones around the world to study how pollution and climate change are impacting mesophotic reefs. Tag along with our Hope for Reefs team as they conduct mesophotic research in Roatán and the Maldives.

^{Bart Shepherd photo: Luiz Rocha © California Academy of Sciences}