Originally Posted by Tropical Aquarist
They shouldn't change color much, it's more having different kinds/colors mate will lead to wild colored offspring.
Just remembered, they do try to fit in with their surroundings, so if you keep them on white substrate they'll have a more full color than on black or dark substrate... That could also be the case.
Pick a good quality Yellow Fire or Orange Sakura (I'd go with Orange or even a Rili), both would pop on plants or rocks.
I think the above was mistakenly noted backwards, yes color tries to match the substrate or surroundings to some degree. BUT Darker with black/darker substrate and lighter with white substrate.
Shrimp of color morphs - some more than others, tend to need culling for maintaining optimum color, some severe culling. Males tend to be lighter color than females as well.
With such a large tank you can maximize your school or fish selection by choosing beautifully colored fish so they are impactful visually on their own, or a school of fish with some color as the group all together would be interesting to observe.
Just consider the shapes of the fish as well in case you might consder a couple options like two or more schools, for example a Neon body shape vs. a Harlequin body shape, are more interesting together than 3 schools with Rummy nose, Neons and Glowlight tetras (bascally same body shape).