lots of things affect mature color....food affects the end result I found thru the years. I started with fh in 2003 and only feed hakiri, and using some of the inhancement foods, I noticed color was really altered. But like some others said the fish may be bored, and most older fish fade. water quality, lighting ,and interaction affect all fish, dont leave hime in a low dark tank in a room no one walks by and expect full potential... Just so of my experiences with fh!! But leas great looking for that head