red cherry shrimps

I have been trying to catch a pic of this little shrimp for a couple of weeks, and it was finally out in the open. All of the other Red Cherry Shrimp in this 10 gallon tank have normal coloration of various shades. What do you guys think could be the cause of this?

Hello! This is my nano tank (3months) 45x28x30cm ELU aqua soil 2x 5w 6500k led (8h) filter aquael versamax fzn-1 Bucephalandra Anubias barteri var. nana glossostigma elatinoides Hemianthus micranthemoides Christmas Moss Heterandria formosa 10+ shrimps neocaridina 20+ CO2 JBL Ferropol JBL...

I have been given a 15 litres tank and have planted it densely with low growing plants . I am wondering is this suitable for red cherry shrimps and am wondering how many to keep in there . Care tips are also welcome