Most of the time, if a venture into the water provokes an encounter with a jellyfish, the swimmer will not be happy. Even tentacle-less jellyfish can be deadly. Typically, swimming in a lake eliminated the risk of a jellyfish encounter. Except in the island nation of Palau in the South Pacific. Palau does have a lake filled with jellyfish, but fortunately for swimmers, they are totally harmless and even enchanting as this video reveals.
A snorkeler visiting Jellyfish Lake caught the dreamy footage of tiny delicate pink and golden jellyfish floating by, and a user with the name mikeyk730 posted it on Youtube.com. Christopher Jobson writes for Colossal: "Every morning the entire jellyfish population migrates from the east side of the lake to the west side, and then back again in the afternoon, causing a near constant flurry of activity as seen in the video."
The lake holds saltwater because it once was connected to the ocean. About 70 such lakes spot the archipelago of Palau. This jellyfish lake is on rocky Koror island and home to the golden jelly (Mastigias papua etpisoni) and less common moon jellies (Aurelia species). For Atlas Obscura, Joshua Foer writes:
The isolated lakes became the perfect setting for a jellyfish explosion, which some speculate were trapped in the lake 12,000 years ago after a rise in sea levels post-Ice Age. Feeding on quick-growing algae and with no predators to keep them in check, the jellyfish now completely pack the small lake.
Snorkeling is allowed and popular for tourists, but it might not be great for the jellies. Matt Harding, a traveler who became famous through his dancing videos, notes in his book that it’s easy to damage the animals’ fragile bodies. "It’s virtually impossible to swim in the lake without perpetrating a massive slaughter," he writes. So enjoy the video instead.