Sand sifter goby not sifting

[Clown7]

I’ve had my sand sifter for about 2 weeks and sifted for about a week but now he has stopped. He seems to have a funny face tick, but eats well. Any suggestions

 

[nereefpat]

If eats eating, then I wouldn't worry too much.

What species?

 

[Clown7]

Yellow headed sleeper goby