strange watchman goby behavior

[Neros503]

we've had our yellow watchman goby for almost three months now, bu in the past week, he's been acting really weird. He keeps swimming to the top of the tank and around the glass, then he perches on top of my rocks. He also keeps making new holes all around the tank, living in them for a little, then making new ones.
here's a video of his strange behavior. I've never seen him like this before.

 

[MnFish1]

Unfortunately, I cant see the video - BUT - I have had numerous Watchman Gobies that go all over the tank, and others that sit in one hole. (I've also had a couple that jumped out - before getting a lid - so clearly they swim up to the top). The times when mine have stayed 'in one place' are usually when there are pistol shrimp in the tank

 

[jtlmnop]

I added a YWG to my tank about 4 weeks ago. For the first few days, it would charge the top of the tank and generally act freaked out. Then he settled into a hole about 3 inches up in a rock structure. It only pokes its head out to eat when I target feed. Otherwise, I never see it out, and has yet to touch any sand. So, no sand sifting from this goby! At least not yet...