Yellow watchmen goby turn grey?

[Fishyyy]

When I first bought my Yellow Watchmen Goby few months ago he was grey when I got him with blue on his anal fin, ever since he has been more active in the tank with my pistol shrimp as well he looks like he is turning yellowish around his face. Could he be turning yellow again?

 

[little_fish]

Very likely, they tend to change colors when stressed or between day/night

 

[d2mini]

Mine was always gray.
Well not when i got him, but after a while he turned gray all of a sudden and then stayed that way. My LFS told me it happens all the time in captivity. He stayed that way until the great fluval edge tank crash of 2012. May he rest in peace. :(