Physical Description

  • The bell (body) is bowl-shaped and white, with a radial pattern of 16 purple stripes on the bell of the adult.
  • Bell can be up to 3 feet in diameter and tentacles can be as long as 25 feet.
  • The tentacles consist typically of eight marginal long dark arms, and four central frilly pink oral arms.
  • The four frilly oral arms may be missing in older individuals.
  • Juveniles lack the purple stripes on the bell, and their bell is pale pinkish in coloration.
  • Juveniles’ tentacles are dark reddish instead of purple.


  • Live off the coast of California, often near Monterey Bay.


  • Primarily pelagic, in nearshore open waters.


  • Their lifecycle was not understood until 2008, when scientists observed they have both a sexual and asexual phase.
  • In the sexual stage, male adults transfer strands of sperm from the tips of their oral arms to the tips of the female’s oral arms and tentacles.
  • The female transfers the sperm to her gastrovascular cavity and fertilizes the eggs.
  • She then moves the eggs to her oral arms where they are brooded and become ciliated larvae.
  • These larvae break off and swim to a suitable hard surface that they attach to upside-down.
  • This starts the asexual stage. These upside-down larvae morph into polyps, that grow tentacles to feed with.
  • These polyps then bud off genetically identical clones one at a time when conditions are not ideal.
  • When conditions are ideal, the polyps can also make strobila, which are stacks of tiny identical clones, all just a quarter of inch in diameter, that swim off together.
  • The strobila grow into the adult form in 2-3 months.


  • Zooplankton, including copepods, larval fish, ctenophores, salps, other jellies, and fish eggs.


  • Primarily preyed upon by leatherback turtles.
  • Also eaten by sunfish and sea turtles.

Interesting Facts

  • They are also known as the purple-striped sea nettle.
  • They are often found with young slender crabs hitching a ride in the jelly’s bell. The crabs get a free ride on the jelly, and the crabs eat parasitic amphipods that damage the jelly.
  • They have a strong painful sting, but it is not fatal. 

Sources: Monterey Bay Aquarium; National Aquarium; Graham et al. 2010; Aquarium of the Pacific; Scripps Zooplankton Guide

Photo: Tracy Clark