moon jellyfish

Moon Jellyfish-Facts and Photographs

Moon Jellyfish


  • Moon Jellyfish are easily recognizable by the pattern of four joined circles on the top of the jelly fish created by its gonads which are visible through the transparent bell.
  • They are single sex organisms being either male or female.
  • They consist mainly of water.
  • Their food is Plankton, including small shrimps, fish eggs and other floating larvae.
  • They are found across the world and have a wide range of temperature tolerance from 6 to 31 °C.
  • They feed on plankton and grow up to 40 centimeters in width.
  • The adult and larvae of Aurelia have nematocysts or stinging cells to capture prey and also to protect themselves from predators.
  • The animal lacks any respiratory, excretory, and circulatory systems.
  • Respiration occurs by diffusion across the cell wall of the organism.
  • As the oxygen rate in the ambient water drops so the jelly drops its rate of respiration.
  • They have a subumbrellar nerve net within the structure that is responsible for controlling contractions in the coronal muscle in the bell that allow it to swim.
  • The moon jelly has rhopalial centers, which allow it to control the pulsations of the coronal muscle.
  • They swim horizontally and tend to stay near the surface.
  • The adult has a has an umbrella margin membrane and tentacles that are attached to the bottom of the membrane.
  • A wide variety of predators eat the moon jelly, ranging from fishes, turtles and birds.
  • They probably live for about six months in the wild but in captivity under ideal conditions can live for several years.
  • The eggs are fertilized in the female when she ingests floating sperm given out by a male.
  • The eggs develop into larvae that free float until they anchor onto a substrate.
  • The larvae grow into an organism that resembles an anemone which splits up into organisms that grow into the adult.



See the moon jellyfish in action:


Moon Jellyfish are mainly kept in large commercial aquariums, but as the knowledge base on these jellyfish has expanded it has become possible to keep them in a home aquarium. It is a fairly complex technical task and depending on the ambient temperature of the specific residence, a water chiller will almost certainly be needed to keep the temperature within their preferred range. A good filtration system and carefully designed water flow  are necessary. A well lit tank full of Moon Jellies can make a very attractive addition to a home.


Occasionally when conditions are right moon jellyfish congregate in large numbers, a so called bloom.  One of these blooms can be seen in the video below which was filmed in Dar es Salaam , Tanzania.


Domain: Eukarya

Kingdom: Animalia

Phylum: Cnidaria.

Class: Scyphozoa

Order: Semaestomeae,

Family: Ulmaridae

Genus: Aurelia