Invertebrate
Golden jellyfish
Mastigias papua etpisoni
An endemic Palau subspecies living only in Jellyfish Lake. It hosts symbiotic algae for much of its energy and makes a daily east–west migration tracking the sun. Nearly harmless to swimmers and snorkel-only; its numbers swing with drought and El Niño from millions to a few thousand.
- Max size
- Bell to ~14cm
- Habitat
- Stratified marine lake (top oxygenated layer only)
Best places to dive with Golden jellyfish
| Month | Likelihood |
|---|---|
| January | occasional |
| February | occasional |
| March | occasional |
| April | occasional |
| May | occasional |
| June | occasional |
| July | occasional |
| August | occasional |
| September | occasional |
| October | occasional |
| November | occasional |
| December | occasional |
Present year-round but drastically reduced in 2025 (a few thousand versus a historic ~5 million); best viewed mid-morning in the dry season. Snorkel-only.
Sources & last checked
Checked July 2026
This is a researched draft, not yet human-verified. The seasonality and logistics are drawn from the sources below — confirm specifics (permits, fees, closures) with an operator before you book.
- Jellyfish Lake — Coral Reef Research Foundation
- Palau Jellyfish Lake — Palau Dive Adventures
Note on the data: Endemic subspecies not assessed by the IUCN, so conservationStatus is recorded as unknown.