Why is my emerald crab white?

[Emarley]

Hello fellow reefers,

Ever since I added an emerald crab to my tank he has been white in colour, other than that he seems happy and is constantly grazing on hair algae.

Thanks in advance

Dom

 

[ChiSox Rabbitfish]

Not sure but Ive seen some whiteish emeralds at the LFS I even seen some reddish ones before also