Wow from a hammer of all things, I say that because I move corals all around my tanks, hell even by BTA and never have a reaction to any of them. It could be due to repeated stings from being a PADI dive instructor of many many years and getting my butt stung a lot teach students what not to do all those years, but I just went in to my tank to my hammer and frog spawn and nothing at all. Now the important question to they decide to sting or is it just on any touch. Maybe mine like me and dont sting lol..