Small box jellyfish at Maslins Beach

My girlfriend and I discovered a small box jellyfish while snorkelling at Maslins Beach in South Australia. We tried to catch it but we lost sight of it shortly after spotting it. We got a good look at it and it was definitely a box jellyfish with four distinct blue tentacles with more tentacles that were uncoloured. It seemed to be alone and we spotted it around the shallows when the tide was coming in and also spotted some blue crabs around the area.