Stingless Jellyfish (Ubur-ubur tak menyengat)
Mastigias-type
In sheltered marine lakes, Mastigias-type jellyfish can be abundant and largely harmless to swimmers.
HabitatIsolated marine lakes and enclosed lagoons
DietPlankton plus symbiotic algae
SizeUsually 8-10 cm bell diameter
BehaviorSlow drifters; gather in sunlit water; daily movements
Where you might see it
At Lake Mariona (Jellyfish Lake) where swimmers can float among dense groups of gentle jellyfish.
How to spot it
You will see soft, amber dots pulsing just below the surface in still water. Enter slowly and let eyes adjust.
Responsible Encounter Guidelines
- •Dont touch or scoop jellyfish.
- •No fins (can injure them); float gently.
- •Avoid sunscreen oils in lake.
- •No soap or shampoo before swimming.
- •Keep noise low; respect local rules.
Gallery
Conservation Status
Highly sensitive to pollution and temperature shifts in enclosed lake ecosystems.