Color-dependant hardiness?

[gusmanda]

Assuming we are talking about the same species, are certain color sps hardier than others? My LFS guy was telling me that in general it is more complicated to retain the color in purple/pink/blue sps than other colors. Wondering whether there is a technical reason for it, or whether in general species with blue/pink/purple coloration tend to be harder to keep than species that tendo to have other colorations?

[sportzfish]

I think there may be something to it since there are so many green varieties available that are not as desirable maybe because they are too easy to keep.

[gusmanda]

is blue colored ones the most difficult?