Sailfin tang face turning black?

[chad8282]

Have had this Sailfin for a few months now and I’m noticing his front face turning dark black is this normal? Also lots of dots

 

[LAA]

Yes, that is completely normal.

 

[chad8282]

Yes, that is completely normal.

Would that suggest his alage intake is proficient Causing more colors? Never really put in the sheets on the clip because I don’t mind having lots of alage on my glass and rocks and he picks away all day on the back wall where it’s dense alage