Goby changing?

[DeaFkiD]

So I bought a goby about a month ago I loved his colors and how he sifts the sand, I don't remember what petsmart had him labeled as but he was gray with vertical stripes. But recently his back half started turning blackish and now when I came home tonight his head had turned white and he is getting red dots. So my question is it possible for the breed to change?( I know stupid question) or was he not mature and now he is maturing to an adult?

 

[bribo12]

So I bought a goby about a month ago I loved his colors and how he sifts the sand, I don't remember what petsmart had him labeled as but he was gray with vertical stripes. But recently his back half started turning blackish and now when I came home tonight his head had turned white and he is getting red dots. So my question is it possible for the breed to change?( I know stupid question) or was he not mature and now he is maturing to an adult?

Fish cannot change species. He is probably getting better color due to being in much better water quality and eating healthier. Or the opposite is happening.

 

[marsh]

He could be maturing from juvenile to adult, not a bad guess. Look at gobies online to find a similar one and find out his species. Try LiveAquaria.com and you can read up on the details of that species