Jellyfish Lake in Palau

Photo: Helen Pippard/IUCNWeb/Flickr

Where the jellies roam

Nestled within a lush forest on the Micronesian island of Eil Malk is one of the world's most remarkable snorkeling destinations: Jellyfish Lake. The freshwater diving spot, located in Palau's Rock Islands, is named quite literally for the millions of jellyfish that spend their days bobbing back and forth across the lake's length.

While many cnidarians are known for their lethal stings, the two species that live in this lake — the moon jellyfish and the golden jellyfish — are harmless, making them perfect swimming companions. Protective stingers were rendered mostly pointless after the gelatinous, glass-like creatures evolved in a closed environment with few predators.

These beautiful jellies may be one of a kind, but they aren't the only freshwater species. The most prolific example is the Craspedacusta sowerbii, which is found everywhere from the Ohio River to the Wang Thong River in Thailand.

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Catie Leary is a photo editor at Mother Nature Network. Follow her on Twitter and Google+.