… there are jellyfish or stingrays in the water?
Most jellyfish are not too dangerous. Swimming in Australia I have experienced little electric stings, which I don’t even notice with the adrenaline of racing. If you do happen to have a problem during the swim course, lifeguards are always there to help, so stay calm and swim over to a guard if you’re bit and you don’t think you will be able to finish the swim. That being said, I truly feel that race directors put on races in safe conditions and would not have swimmers race in anything that could negatively affect athletes’ health.