I know, I hate jellies! It's box jelly season at the moment, so I just stayed off the beach. They do have nets, but those things have metres of tentacles, so they can reach through the nets. Why risk it? Luckily, they hang around the coast, not on the reef, so we could swim out there. :) Got stung by many tiny ones, though. We had anti-jelly suits, but they got my hands and face. There were heaps of non-boxy ones out at sea away from the reef, too.