One additional thought related in breeding to culling is adding in a different group of shrimp/ breeding genes. That could go very well but also may not go as expected./QUOTE]
Are you saying a different color? Once this group is having babies consistently, I had planned to buy an additional group of Jades to reduce deformities from inbreeding.
Yes because the colors are derived from one line of breeding adding shrimp from a different line MAY, maybe not be an issue, but not absolutely cause other / different line to change. There are many breeders which do not add shrimp for many generations. As in years.
Line breeding is in a group of shrimp breeding in a long line of breeding. Culling for the color especially, but also for the shape and desired traits.
A different line added in can add a whole different dynamic, genes. Once you have a solid breeding group which continues producing the shrimp babies you want you could try taking a best male and or couple females and try with a new male and or females to see how the babies produced come out.
If getting any new shrimp, it is best to QT them for a couple months or so to make sure there isn't any illness from the new ones.
To be honest, most people don't give this much thought. But in the breeding there are lots of things to learn about. If it is simply for a fun project of your hobby it probably doesn't really matter that much.
But being able to produce amazing shrimp to sell at a high amount because they are actually valuable and worthy is even more exciting.
Look up award winning shrimp.
This isn't an award winner that I know of but here is a really fine looking shrimp. Good looking body color
https://buceplant.com/products/green-jade-shrimp
Lower grade green Jade
https://www.reddit.com/r/shrimptank/comments/bdv408/they_called_her_a_low_grade_green_jade_i_think/
Again like you mentioned in the reference of culling in breeding and very serious breeders usually do not even preserve the cull shrimp. Because they aren't representative of the top of the breed.
Usually hobby breeders mostly just love shrimp and want to keep their line good/ make it better.
Like you said you prefer the darker green. So that would be what you would like best, and breeding for. Someone else might like medium green. Someone else doesn't care as long as they are shrimp of any color.
The shrimp which caused me to get interested in Dwarf Shrimp back in 2011 were OEBT / Orange Eye Blue Tigers. As the years went by more and more people preferred the deep near black blue shrimp. I'm interested in the Royal Blue ones. My favorite color, which is harder and harder to find!