The bluebottle (physalia) is probably the most well known jellyfish around the Australian coastline. Their blue, balloon like sail sits above the water and is attached to a long tentacle extending below it. This tentacle is covered in stinging cells called nematocysts. When this touches the skin it reacts by injecting a small amount of a toxin which causes irritation and can be quite painful.
How to treat a sting:
There are also many types of sharks around Australia. Most are harmless to humans. Although humans fear sharks, they are an important part of the ecosystem and a reality of the ocean.
Tips to minimise a shark encounter: