Stingrays are a massive problem (moreso than sharks ) and should be getting the press they deserve .(i'll see if i can find the photo of bigwave daves leg)There are only leeches in freshwater so avoid freshwater creeks and rivers .Again there are other nasties that don't get the press they deserve like bull routs (they burrow into your foot and live in lakes like Tuggerah,lake macquarie) and razor shells that stick up in those lakes too and will slice you open
Australia is a dangerous place and there are more things to worry about than funnel web spiders,red backs and did I mention snakes?We are a hard tough lot down here so HTFU

and yes WA is best