Yeah they always hide, mine defends his territory quite fervently lol. Forbid any fish go near his den, he barrels around and spooks the poor frontosa.
let your bgk get comfortable...he may eventually come out. for a month or 2 i didnt even see my bgk. i just put his food in the fake log and he will eat there. now i see him all over the tank. also what are his tankmates? i noticed my bgk hates fast moving fish and tends to hide more when those fishes were in the same tank.
give him a month or two and theres a good chance he will be less shy also try slowly placing his food further away from where you normally would...small distances ata time and coax him out
Mine hides a lot right now. I've had it for about a week now. Still eating from what I can tell. I know his favorite spot (which is in a crook of some driftwood). So fortunately, I can still seem him every time he just won't come out.
I even woke up at 230 this morning just so I could see him swimming about. I want him to become more active in the daytime. I typically just try feeding him at the same time as my others in the tank. He's like a little puppy dog. Rubbing up against all the other fish and decor. lol