Is the rock in your tank yet? can you pull it out easily?
If so, take the rock he is in, find his hole and spritz a little FW
into the hole with a turkey baster. He should come jumping out so be ready.
Oh and don't try and pick him up with your bare hands. A strike from him would hurt.
They are preditors so if you can get him now, all the better.
Also consider setting up a small tank for him. They are interesting as long as they are not in a community tank.