Is your tank covered? Jawfish are one of the worst fish out there for jumping, they'll jump if something in the room moves. They're incredibly shy, nervous fish and that's probably the reason he's not eating yet. They need a burrow where they can see 360 degrees around their burrow in order to start to relax and not feel threatened, they also need several inches of rubble substrate (ie not just sand) that they can burrow in and it not collapse.. Hate to suggest it, sorry, but you may want to consider selling him or give him away at this point to a tank where he can have that if that's not in your short term plans, otherwise I don't think he will be a long lived fish for you. I had a pair many many years ago (pushing ten) and while they were beautiful fish I do have to say you could really sense their misery when the setup is not 100% to their liking. It's not a fish I myself would try again unless I could have them in a smallish but dedicated setup for them that even included mirrors on the sides and backs so that room activity doesn't startle them.
And the mystery fish is a blue assessor eh? Neat. Looking forward to the pics..
