What is the name of the lake in Palau famous for its non-stinging jellyfish?

The lake in Palau famous for its largely harmless jellyfish is Jellyfish Lake. It lies on Eil Malk island in Palau’s Rock Islands, a limestone archipelago containing roughly 70 marine lakes. The lake is connected to the surrounding ocean through cracks and tunnels, but its isolation has created unusual ecological conditions.

Millions of golden jellyfish, commonly identified as Mastigias papua etpisoni, migrate across the lake each day. They follow sunlight because symbiotic algae living in their tissues provide much of their energy. Although often called “non-stinging,” these jellyfish do possess stinging cells; their stings are generally too weak to harm people, though sensitive swimmers may notice them.

Jellyfish Lake formed roughly 12,000 years ago as post-Ice Age sea levels rose and flooded an ancient basin. It is permanently stratified: oxygen-rich water occupies the upper layer, while deeper water contains little oxygen and hydrogen sulfide. That is why visitors snorkel at the surface and scuba diving is prohibited.