This undated handout picture taken by Tim Samuel and provided through his Instagram account shows a small fish swimming inside the belly of a jellyfish off the coast of Byron Bay in New South Wales, eastern Australia. A fish has been pictured swimming inside a jellyfish off Australia's east coast in a remarkable and rare image that has gone viral, with more than two million online views. Underwater photographer Tim Samuel was in the water with a friend near popular tourist resort Byron Bay in December when they came across the little creature trapped inside the only slightly larger jellyfish. (Photo by Tim Samuel Photography/AFP Photo/Instagram)

Project Mermaids model. Project Mermaids lets ocean-lovers don tails and live out their siren fantasies. Clients can pay for a shoot that is either on land or underwater, with the images looking to raise awareness about preservation of beaches, seas and oceans. The project – which is shot by photographers Angelina Venturella and Chiara Salomoni – started purely to raise awareness, with celebrities dressing up as sirens as part of the cause. (Photo by Angelina Venturella/Chiara Salomoni/Caters News Agency)

A model poses with a crocodile at Chinchorro Banks, Mexico on June 21, 2018. These crocs had a lot to smile about – sporting huge toothy grins as they posed with stunning models in incredible underwater snaps. The brave models held their breath as they came face to face with the magnificent predators during the daring shoot. Photographer Ken Kiefer took a two hour boat ride to reach the carnivorous crocs at Chinchorro Banks, Mexico, along with his wife and model, Kimber and model, Melodie Trevino. (Photo by Ken Kiefer/Caters News Agency)

Brian Skerry can be called many things – explorer, journalist, conservation advocate – but he is first and foremost a photographer. His journeys to capture amazing underwater photographs have taken him across the world’s oceans. Photo: This Bahamian oceanic whitetip shark, known for the distinctive coloring on its white-tipped, rounded extremities, is part of a globally threatened species due to overfishing demands, primarily for its fins. (Photo by Brian Skerry)

“These incredible shots show the stunning formations of an iceberg beneath the surface of the ocean. Taken in Tasiilaq, Greenland, by Franco Banfi, the underwater photography captures the beauty of these ice mountains beneath the ocean’s surface. In some of the photos, divers are swimming around an iceberg under the frozen water, while other images show some of the weird and wonderful creatures you can encounter in that part of the ocean”. (Photo by Franco Banfi/Caters News Agency)

The NASA Extreme Environment Mission Operations (NEEMO) 21 mission began on July 21 as an international crew of aquanauts splashed down to the undersea Aquarius Reef Base, located 62 feet below the surface of the Atlantic Ocean in the Florida Keys National Marine Sanctuary. The NEEMO 21 crew will perform research both inside and outside the habitat during a 16-day simulated space mission. During simulated spacewalks carried out underwater, they will evaluate tools and mission operation techniques that could be used in future space missions, including journeys to Mars. (Photo by Karl Shreeves/NASA)

“For centuries, the Moken sea nomads have traveled the islands between Thailand and Myanmar fishing and foraging for food on the sea floor. Throughout the Mergui Archipelago, Moken migrate in flotillas of Kabangs (traditional boat of the Moken people), stopping at different islands and beaches. Expert freedivers, the Moken have adapted physically to an aquatic life, developing unique characteristics that let them see better and hold their breath longer while underwater”. – Taylor Weidman. Photo: Hook, an indigenous Moken man, holds a three-pronged throwing spear and searches for fish in the waters of Ko Surin National Park. March 1, 2013 – Ko Surin, Thailand. (Photo by Taylor Weidman/zReportage via ZUMA Press)

In this May 2016 photo released by The Ocean Agency/XL Catlin Seaview Survey, a boat sails near a coral reef that has been bleached white by heat stress in the Maldives. oral reefs, unique underwater ecosystems that sustain a quarter of the world's marine species and half a billion people, are dying on an unprecedented scale. Scientists are racing to prevent a complete wipeout within decades. (Photo by The Ocean Agency/XL Catlin Seaview Survey via AP Photo)