Jellyfish Lake - Ongeim’l Tketau - Rock Islands
Jellyfish Lake, or Ongeim’l Tketau, is one of those spots that feels like stepping into a documentary. It’s not a dive site in the traditional sense, more a unique snorkel. You swim through layers of golden jellyfish, *Mastigias papua*, pulsating gently around you. They're non-stinging here, having evolved without predators, so you can float right among them, feeling their soft bodies brush your skin. It’s a calm, almost meditative experience, totally unlike open-ocean diving and perfect for anyone looking for something truly different.
- Location
- Rock Islands, Palau, Central & South Pacific
- Coordinates
- 7.160900, 134.376700
- Maximum Depth
- 12m
- Difficulty
- Beginner
Marine Protected Area: Rock Island Southern Lagoon Management Area
Best Time to Dive in Rock Islands
The warmest water temperatures in Rock Islands occur in October, averaging 30.0°C. The coolest conditions are in February at 28.4°C.
Monthly Water Temperatures
- January: 28.8°C
- February: 28.4°C
- March: 28.8°C
- April: 29.3°C
- May: 29.8°C
- June: 29.9°C
- July: 29.8°C
- August: 29.7°C
- September: 29.9°C
- October: 30.0°C
- November: 29.9°C
- December: 29.6°C
Nearby Dive Sites in Rock Islands
- Big Drop Off - 20-40m (wall)
- Blue Corner
- Blue Corner (and Blue Holes)
- Blue Holes
- Chandelier Cave (cave)
- Chandelier Caves - 34m to 98m
- Chuyo Maru (wreck)
- German Channel - 21m (drift)
- Helmet Wreck - 34m to 98m (wreck)
- Iro - 16-131ft (5-40m) (wreck)
- Iro Maru Wreck Palau - 27m (wreck)
- Jake SeaPlane (wreck)
- Lighthouse Channel (drift)
- Mandarinfish Lake - 16-131ft (5-40m)
- MT ARAYAT - 0m (wreck)
Nearest Dive Centres to Jellyfish Lake - Ongeim’l Tketau
Marine Life in Rock Islands
Home to 198 recorded species including 171 reef fish, 15 sea cucumbers, 4 clams & mussels, 4 sea snails & nudibranchs, 2 starfish, 1 sea urchins.
Notable Species
- Boring Clam (Tridacna crocea) - Clams & Mussels
- Small giant clam (Tridacna maxima) - Clams & Mussels
- Black sea cucumber (Holothuria atra) - Sea Cucumbers
- Orange-lined Triggerfish (Balistapus undulatus) - Reef Fish
- Pinkfish (Holothuria edulis) - Sea Cucumbers
- Saddleback Butterflyfish (Chaetodon ephippium) - Reef Fish
- Greenfish (Stichopus chloronotus) - Sea Cucumbers
- Bristle-toothed Surgeonfish (Ctenochaetus striatus) - Reef Fish
- Burrowing urchin (Echinometra mathaei) - Sea Urchins
- Bullethead Parrotfish (Chlorurus sordidus) - Reef Fish
- Tigerfish (Bohadschia argus) - Sea Cucumbers
- Threadfin (Chaetodon auriga) - Reef Fish
- Telescopefish (Epibulus insidiator) - Reef Fish
- Banded Goatfish (Parupeneus multifasciatus) - Reef Fish
- Kihikihi (Zanclus cornutus) - Reef Fish
- Banded maori wrasse (Cheilinus fasciatus) - Reef Fish
- Sunburst Butterflyfish (Chaetodon kleinii) - Reef Fish
- Curryfish (Stichopus vastus) - Sea Cucumbers
- Butterfly fish (Chaetodon vagabundus) - Reef Fish
- Honeycomb Grouper (Epinephelus merra) - Reef Fish
Recommended Packing List for Jellyfish Lake - Ongeim’l Tketau
Based on average water temperature of 29.5°C, currents 13 cm/s.
- Shorty or Rashguard - warm 30°C water needs minimal exposure protection
- Mask - essential for every dive
- Fins
- BCD - buoyancy compensator
- Regulator - your most safety-critical piece of gear
- Dive Computer - tracks depth, time, and NDL
- Surface Marker Buoy (SMB) - essential for boat pickups
- Dive Torch - useful for crevices and colour at depth
- Underwater Camera - capture your diving memories