Shrimp experts kindly reply ?

So I have a huge 125 gallon aquarium with a lot of community fish and one 5-6 month old Red cherry shrimp, she is huge and is doing great, the only downside is she is alone in the big tank, then I made a small 6 gallon shrimp tank and have been cycling since November and recently have added 6 cherry shrimp and 2 weeks in and they are doing good, one was berried so I have a week old shrimplets too, so my question is should I shift the single shrimp from big tank to this small tank ? She is huge compared to the 6 I got, ( she is almost double their size) also the big tank has a TDS of 250-300 and my Shrimp tanks TDS is almost 140. What should I do ? Leave her in the big tank and let her enjoy her life or shift her to the 6 gallon tank ? What is better for her ? I don’t wanna add new shrimps to the big tank since most of them gets eatten away by my fishes.