Avoid the six line at all costs. They are nightmare fish (I personally believe they’re worse than the Jade Wrasse). I have worked in an LFS and it got to the point where we only got them in if people asked for them. I have kept 4 personally, all 4 were good however there was 80+lbs of LR in the tanks. These fish need a ton of hiding spots to be happy and not claim a tank.
I recommend looking into these genera:
Wetmorella
PseudocheilinOPS
I have kept a species from both genera (Tanakai Possum and the Pink Streak) and I loved both, my preference was the pink streak as they get a bit bigger and so aren’t as likely to become food to any inverts.
This was my Juvenile Pseudocheilinops ataenia
And this was my mature Pseudocheilinops ataenia
You can really see the resemblance between the pink stream wrasse and the six line wrasse. They’re closely related however the pink streak doesn’t become a bully unlike the six line. My pink streak also did a relatively good job at keeping pests out of the tank.