I notice that you have him with your other fish. Is it possible that he doesn't like the competition for food? What if you had him in a 20g long for instance by himself. Those live brine will swim around twitching and enticing for hours. Maybe if he was isolated, he might be inclined to eat. I'm sure that once you get him eating, he will be fine. But if he wasn't eating at LA, and he hasn't eaten for you in two weeks, he may very well reaching the critical zone or point of no return.