...actually, you are never supposed to pick them up by the tail for that very reason. It's why I refuse to have any 'psycho' rats in my house - since you can't pick them up via the tail and if you try the normal way you get bitten. As one who got nailed on the NECK by a psycho rat as a youngster (and yes, I still loved them as pets but I was always careful to make sure they were calm) I stick to that rule like glue!

A great way I would use to move mean rats was to 'coax' them into a long box, then move them in the box to a holding tub/cage.