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Have you seen the Freshwater jellyfish? yes, these harmless creatures could be in freshwater near you!

Freshwater Jellyfish (Craspedacusta sowerbii)
Click to enlarge - Freshwater Jellyfish

Perhaps when looking in your local waterway, you may be the first to discover them!!

It is not known if they are here in the Dry Tropics. However these amazing animals occur across all continents (except Antarctica) and in SE Asia.

JCU researcher Lisa Gershwin’s interest in these jellyfish is collaborative and her focus in on their potential control of mosquitoes and cubozoan classification. Reporting details are at the end of this flier.

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General Information

Where: commonly found in man-made reservoirs, dams, ornamental fish ponds, shallow pools, and slow-flowing waterways. Strictly found in freshwater, i.e., water in which naturally occurring salts cannot be tasted (though it is not typically a good idea to test it this way!). 

Nature of the animal:  about the size of a 5- or 10-cent piece, delicate and lacy-looking, colourless to whitish, typically in relatively large numbers when they occur.

Seasonality: Typically found in the summer months, but may be found all year long in the tropics throughout the world. However, each sub-population blooms and disappears in a number weeks to months, not appearing again at that location for perhaps 5-10 years.

Natural history notes: scientists think they are transported from pond to pond on the feet of waterbirds. They eat small aquatic invertebrates and larvae, including mosquito larvae. Probably an important part of the food chain, because despite their small size, they are thought to have no natural predators.

Sting: mild to non-existent. It is possible to swim with them without harm, although people with sensitive skin (such as young children and the elderly) may feel some irritation. Those with known allergies to stings of any kind should not swim with them.

Although it is not known if they occur in the Dry Tropics, these harmless creatures could be in freshwater near you!!

And they may benefit us as they eat mosquito larvae!

Technical Information

Life cycle: they have a complex life cycle, wherein the medusa (= the jellyfish phase of the life cycle) is budded off from a hydroid (= a tiny creature which looks like a sea anemone, only fractions of a centimetre tall).

Distribution: found worldwide in tropical and temperate areas. Within Australia, it has been found in all states except Tasmania. In Queensland, it has only been found at the Enoggera Reservoir in Brisbane, in 1964. However, scientists strongly believe that they are present in many other locations around Queensland, and some of these populations may be species that are new to science! 

Species and meaning of names: there are thought to be at least 10 species within two genera, Craspedacusta and Limnocnida. Only 3 species in the genus Craspedacusta have been found in Australia, two of which proved new to science.

Craspedacusta translates to “border guard”, in reference to the stinging tentacles along the border of the body (from the Greek “craspedo”, meaning border, and the Latin “custos”, meaning guard.

Limnocnida translates to “marsh stinger”, from the Greek “limno”, meaning marsh, lake or pool, and the Greek “cnido”, meaning nettle. 

Research interests: information about when and where they occur is being sought by researchers from Australia and Germany, in order to study their ecology and evolutionary relationships

Freshwater Jellyfish (Craspedacusta sowerbii)
Click to enlarge - Freshwater Jellyfish

For further information

Lisa Gershwin,
Jellyfish Researcher, JCU Townsville,
office phone 4781 6446,


Visit Conservation Volunteers Australia

Visit James Cook University

Visit Townsville City Council

Visit Waterwatch Australia


Visit the U.S. website on freshwater jellies at:

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