My tank is 29gallons, with about 40lbs of live rock, an AquaC Remora skimmer. I have a Fluval which I've decided to not use for filtration as such anymore; will block the in-take tube from getting debris in and just put in some live rock inside and carbon to help with biological filtration. There are 4 power-heads.
I didn't realize Six Lines were so aggressive! I'm hoping an Angel will be able to keep his/her own, but I'm not planning on waiting too long. As soon as the Wrasse goes into the tank (which will probably be this Thursday) I'm putting the next fish into the QT (which will probably be next Thursday. Assuming the LFS I go to has the fish in-stock.)
EDIT: Perhaps I could get a Blenny of some sort? I like the look of the Bicolor Blenny. But I have coral sand, not live sand, on the bottom and I wonder how they'd deal with that! And how does one keep them in the QT where there is no subtrate (though I do have a few pieces of live rock in there.)