Fish pale in color when near cleaner shrimp!

I added a Blood/Fire Shrimp to my tank today and my Yellowtail Damsels look pale...they must have temporarily lost color due to the fact that they are in close proximity of the cleaner shrimp. My damsels entrusted this shrimp within one hour in his new home...they are swimming up to the shrimp's "cleaning stations" to be cleaned of parasites. Right now the shrimp set up shop basically anywhere in the shade and the damsels are almost waiting in line for cleanings! Normally they swim up higher but apparently they know that they have to have to be cleaned of parasites. I find it amazing that fish have an inborn trust and knowledge of cleaner shrimp.

Has anyone else heard of fish losing color in the midst of a cleaning session?

 

my yellow watchman Goby lose some color but hes fine after about 2 minutes my blue damsel dosnt let him touch him

 

Ok cool it must be normal. Thanks for the response.

 

This is a natural response as it makes the parasites on the fish more visible to the shrimp.

 

Wow pretty amazing