Black clown turning grey?

[KingAlee]

Anyone know of any reasons why a black clown would be just turning grey? I have been gone for 2 days (had my first baby born) and my family has watched my tank and FaceTimed me while doing anything with them. Got home and noticed this guy is turning grey or has turned grey. Any thoughts to why? This is with tank lights off, apologies as these are the best pics I could get of the guy.

 

[Mr. Mojo Rising]

Most fish will naturally lighten or darken during the night to sleep, they will return to natural color when the lights turn back on.

 

[KingAlee]

Most fish will naturally lighten or darken during the night to sleep, they will return to natural color when the lights turn back on.

Thank you