Among the fish populations that could be harmed by the Xayaburi dam in Laos is the critically endangered Mekong giant catfish, considered by the Guinness Book of World Records to be the world’s largest freshwater fish. The fish, which grows to 650 pounds and about 10 feet long, is only found in the Mekong River. It is migratory, moving between downstream habitats in Cambodia upstream to northern Thailand and Laos each year to spawn. Some experts fear the Xayaburi dam could block the migration and drive the giant catfish to extinction. (Photo by Courtesy of Zeb Hogan/University of Nevada, Reno)

“7584 Fish”. On a windy day right after a Cyclone passed the far northern Great Barrier Reef i took some friends out to the reef. Never before i saw that many glass fish on this particular coral “bommie”. Just when i setup my camera, this Napoleon Wrasse swam right through the school of fish building a living frame. Photo location: Cairns, Great Barrier Reef, Flynn Reef, Australia. (Photo and caption by Christian Miller/National Geographic Photo Contest)

These unique photos capture the moment a boy has his teeth picked clean by amazing underwater shrimp. These fascinating creatures spend their lives diving inside the mouths of fish to remove the parasites that lurk there. Russell Laman imitated the behaviour of the surrounding fish swarm to entice the cleaner shrimp into his mouth whilst snorkelling with his father Tim Laman in Bali, Indonesia. The 13-year-old queued with the waiting fish and then opened his mouth when the shrimps came near. (Photo by Tim Laman/Caters News)

A fisherwoman repairs the fishing nets at a fishing port during the annual summer fishing ban, which covers the Bohai Sea, the Yellow Sea, the East China Sea, and the waters north of 12 degrees north latitude in the South China Sea, on June 8, 2022 in Wenling, Taizhou City, Zhejiang Province of China. (Photo by Liu Zhenqing/VCG via Getty Images)

Several hundred swimmers took a sunrise dip in the North Sea at Portobello Beach, for the International Women’s Day Swimrise on March 08, 2022 in Edinburgh, Scotland. Women from all backgrounds, abilities and ages come together in aid of Edinburgh Women’s Aid, Edinburgh Rape Crisis and Held in Our Hearts. (Photo by Jeff J. Mitchell/Getty Images)

This photograph taken during a government organised media tour shows people in traditional costume standing in Potala Palace Square as the Potala Palace – classified as a World Heritage Site by Unesco in 1994 – is seen in the background in the regional capital Lhasa, in China's Tibet Autonomous Region, on June 1, 2021. (Photo by Hector Retamal/AFP Photo)

David Bowie wears an eyepatch in red suit and guitar on blue background at Top Pop television studios in Holland while doing playback to his hit song Rebel Rebel in 1974. (Photo by Barry Schultz/Sunshine/REX Shutterstock)

Fisherman transport sharks to the fish market in the traditional fishing port in Banda Aceh, Indonesia, 26 August 2020. According to media reports, the marine and fisheries sector is considered as one of the affected by the coronavirus pandemic, affecting more than 3.5 million fishermen and all sectors working throughout the supply chain. (Photo by Hotli Simanjuntak/EPA/EFE)