LOL....why was his hand in the tank?
Because he has the tank!!!!
We have a 125 that currently contains 8 lions and 3 scorpionfish and my hands are always in the tank.
Admittedly, I'm extremely experienced (reptile hot license and have worked with rattlesnakes, cobras, coral snakes, etc.) and have only been stung once, that being by a wild scorionfish I was transferring out of the capture net by hand.
Here's some basic tips to help avoid being envenomated by your pets:
1) Always move your hands SLOWLY when working in the tank.
2) ALWAYS know where your lionfish is at all times.
3) NEVER trap you fish in a corner, as he's likely to panic and bolt to escape when he feels threatened.
4) Never place your hands over the top of the lion (same reason as #3)
5) When feeding use caution at the water's surface.....many will rush to the top to get their share (especially if housed with other heavy feeders) and on larger specimens, the doral fins will actually project out of the water (accidental, but this does nothing to lessen the pain)
6) If hand feeding, hold the food underwater, so that the lion has to come DOWN to take the food from your fingers.
ps...to avoid cries of "the tank is too small", the volitans in the tank are juveniles, and when they reach suitable size, they will be transferred to our 300 gal. tank.....the dwarfs, however, are permanent residents.