Ok, I feel better knowing I'm not the only one who's Wrasse lost the blue throat. Every once in a while, I'll see its blue darken, but it ends up getting light again shortly. It sometimes flashes to the other Wrasses, especially after eating; I see its body color change rapidly, but throat stays a faded blue.
I also noticed it can get pushy with the other Wrasses. My Labout's, which is by far my biggest Wrasse (already full grown or close to it), had to put him in his place a few times when he starts chasing the smaller Wrasses around. I was actually surprised when I saw the Labout's act like a peacekeeper. It's nice to have a big fish to help maintain tranquility in the tank.