Jellyfish have three parts to their life; a swimming larva stage, an attached polyp stage and finally a current drifting medusa stage.

See-through animals

Jellyfish are cup shaped animals with one opening and a rim of tentacles. They have no heart, blood, brain, ears, eyes or central nervous system and use their whole body to breathe. Their clear body (known as a bell) acts as camouflage, helping them to survive in the open ocean. Moon jellyfish are named for their perfectly round, shiny bell which reflects light, appearing as a full moon in the water. They have cresent shaped reproductive organs that are visable through their bell, adding to their moon motif.

Older than dinosaurs!

The body of a jellyfish is 95% water. Their simple structure has helped them exist for over 650 million years – That means they out-lived the dinosaurs and existed long before sharks or life on land!


Jellyfish use their tentacles to catch prey of small fish, algae, and even other jellyfish. Tiny stinging cells in the tentacles, called nematocysts, paralyze the prey before it is drawn to the mouth and digested.

Free transport

Moon jellyfish are swept around by ocean currents. They can’t swim against these currents, but can swim up and down within them. This free transport works well for jellyfish, as it uses little energy and means they are always surrounded by food, as their small prey also drifts in these currents.


A group of jellyfish is called a smack! Smacks of 1000’s of moon jellyfish can be found all along Western Australia’s coastline and in the Swan River.


Be mesmerised by Moon jellyfish in AQWA’s Perth Coast!