This is Chrysaora chinensis,
the Chinese or Malaysian sea nettle

The bell is small with long trailing tentacles and four oral arms

Tentacles sting and capture prey, oral arms move food towards the mouth

It feeds on zooplankton, fish eggs and larvae, and small crustaceans

Chrysaora chinensis was first described from a specimen caught near Hong Kong in the late 1800's

Sea nettle
Chrysaora chinensis

This species is typically in Hong Kong waters in August and September but has been reported locally as early as July.

The genus Chrysaora can be found all around the world.

Jellyfish like the sea nettle often bloom in warm months when temperatures rise and plankton productivity increases.

Monitoring jellyfish alongside plankton, temperature, nutrients and fishing provides a low-cost integrative indicator of coastal ecosystem health.

A sting from a sea nettle can be painful and even require medical attention.

Research suggests sea nettle venom may have significant anti-cancer potential.