haha ( I can laugh at it now), I remember buying a scorpion fish from a place once, he was in the same tank as the lawnmover blenny and we thought that maybe one is a male and the other a female. Upon closer inspection in my show tank, I realized it was a scorpion fish
. I was scared as hell to put my hands in the tank after reading some horror stories online. Needless to say this guy was enjoying his diet which cosisted of taking all my hermits and snails out, one at a time. Unfortunately for him and fortunately for me (somewhat) I had gotten an ick problem which wiped out the scorpion fish along with my favorite at the time powder blue tang. Oh well, I was just glad he was gone and I could put my hands in there to fix things up.
Anyhow, you don't need a permit, you just need to be very careful and know what to do in the event you get stung in your hands/arms. The solution which seems counterintuitive to most is to put your hand/arm under the hottest water you can withstand and keep it there for a while without of course getting yourself burned. The heat tends to neutralize the toxin; you'd still might have to visit the ER if where you got stung doesn't look like its getting any better.