Gobies supposed to change colors?

[sueandherzoo]

This is the big blue-spot goby I bought a few weeks ago. He was very dark with brown stripes when I first got him, then yesterday he was very "pale" and the stripes were hardly noticeable at all, and today he's kinda yellow with hardly any striping. I didn't think gobies changed colors - is he alright?

 

[debbie]

I would almost say that the goby is a Yellow Watchman Goby. I use to have one of these guys, neat fish.
I have seen yellow watchmans change to a brown color like that when stressed. Mine was not a bright yellow when I first bought him by when he settled in wow he was sure a nice bright yellow with those beautiful blue dots like yours on the cheek.
He looks better in the second pic and I be it is a Yellow Watchman for sure.