Does substrate color affect opae ula?

[Tiny Ocean]

Mustafa, I guess you still keep your shrimp in tanks with the bottoms covered by bracky balls? So, a green "substrate", and they are deep red. I tend to think that, as you have said, opae ula color is a display of stress or comfort rather than an attempt to match their environment. My shrimp seem to have gotten paler since I put them in a tank with a white sand substrate and a white Florida limestone rock. I wonder if it makes them feel more exposed? The reddest ones are big ones that hang out in the holes in the rock where it is shady and perhaps they feel more protected. Maybe I will put some green or brown sea glass on the sand and see if that makes them feel any better. Or replace the white sand with green olivine sand that came from Hawaii before taking it was banned.
https://www.hawaii.com/hawaii-beaches/h ... nd%20green.