Try sinking pellets. I used to place them at the cave opening for my goby and pistol. Your goby is acting normal for a new tank, but he most likely will never swim to the top and compete for food. Some food has got to make it to his depth.
You can get a pistol, but not required IMO
. Are your rocks on the sand or against the glass bottom. Rocks that sit on top of the sand and burrowing gobies and especially pistols are a disaster waitng to happen.
Jimbo, you know you're a nut, right??
"airplane noises" ???