I would get a reef safe wrasse such as: Scotts Fairy Wrasse, Mystery Wrasse, carpenters flasher wrasse...
just be careful the purple pseudochromis are usally pretty aggresive towards other fish
Also you should have a top on your tank if u decide to get a wrasse because they are known to jump out
I wouldn't add a fairy or flasher wrasse in tank with a sixline. Da Reefer, I would keep a close watch on that wrasse. They are very shy and skittish and after you have them about a year they get meaner and meaner.
I am a fan of blennies. No other fish has the personality. I really like Midas blennies.