I too got stung by something last week while aquascaping. I still have no idea what it was I may have just got poked by a sharp edge of one of my rocks. But when I was done I noticed a small round puncture mark on my forearm which was bleeding. I washed it in cold water and rubbed on Benadryl cream. Ten minutes later my arm was red and blotchy from my wrist to past my elbow and it felt itchy. I took a benadryl tablet just in case. I dont know if it was me freaking myself out or the sting itself but my heart rate was definitly up and I was feeling sick to my stomach. Thankfully It passed and when I woke up the next day the rash was gone. The small puncture wound is still visible but it has healed over. Just figured I'd add my story, I am wearing gloves past my elbows for now on. I don't want to be the guy who died aquascaping, because my wife is always telling me to leave it alone it looks fine, If i got killed she would have the ultimate I told u so.