Because the bell is almost transparent the tentacles are the more visible part of the animal. Often you only know the stingers are present when you swim into one and contact the microscopic stinging cells on their tentacles. These stinging cells are used to capture food and they are triggered by contact. When we inadvertently swim into a stinger their stinging cells fire automatically. A sting from the SW stinger often forms a red line.
Jellyfish experts suggest pouring vinegar over the affected skin.
This treatment prevents unfired stinging cells from causing additional stings. Remove any bits of tentacle from the skin with tweezers or a gloved hand. Apply ice, and possibly a pain relieving cream to the affected skin for pain relief. This summer staff of the Museum are collecting stingers for researchers at the University of Melbourne who are working on the venom of the SW stingers and related species from around Australia.