Wrasse for flatworm control in bare bottom tank

[Joe31415]

I have a bare bottom, 20g, invert-only quarantine. As of right now, all of the corals that are in that tank have been in there for somewhere between 2 and 14 months. What started out with me being too lazy to move them to the DT has shifted to me having not moved them because of a some kind of flatworm outbreak.

I'm currently doing my second round of flatworm exit, so we'll see what happens, but in the mean time, I wouldn't mind adding something that eats them. My understanding is that the best thing (fish or invert) for the job is a wrasse. At the moment, I'm thinking either a Six Line or Melanurus.

First off, it from what I'm reading, the Six Line can be mean. Not a big deal in a tank with no fish, but it may end up in the DT when it's job is done. Both because I'm worried about it outgrowing my 20g and having a fish in the invert QT kinda defeats the purpose of an invert only QT. Also, I beleive their jumpers and, if at all possible, I'd prefer not to have a lid on this tank.
I'm also considering a Melanurus Wrasse, but what I'm reading suggests that needs sand in the bottom. I'd prefer not to have a bowl of sand in there, though it's not the end of the world if I need to.

So...Six Line or Melanurus? I'm leaning towards the Melanurus, but I'm not totally set on it.

Also, while we're talking about flatworms, that brings me to another question. I'd like to get some of these corals out the QT and into the DT, but I'd prefer not to introduce flatworms in the DT. Will any dips kill them? I have CoralRX, Revive, Iodide (Iodine?) and hydrogen peroxide.

Also, I'm completely open to other ways (fish or otherwise) to get rid of these. FWIW, my outbreak isn't all that bad. If I sit in front of the tank with a turkey baster, I can probably get 20 or 30 out in 15 minutes. It's not that I have (or that I'm seeing) hundreds or thousands of them.

 

[Pistondog]

Had both, the melanaurus is a little more challenging to make comfortable without a sand bed. He seemed more skittish and eventually damaged his jaw.
Is a bowl of sand enough?
6 line is a good worker and less maintenance.

 

[blecki]

A six line can be mean yes, but they are sort of like chihuahuas. On the other hand I currently own three of them and none of them eat flatworms. I ended up getting three different Halichoeres wrasses to eat them and finally the last one actually ate some. It is a Vrolik, which is very similar to a Melanurus.

A freshwater rinse will instantly kill them on coral - I've only done it to softies though as flatworms don't seem to bother anything in my tank except a few specific paly colonies and a singularia. The palys do not react to the rinse at all. The singularia shrivled up for a day or so but was fine. We're talking a bucket of freshwater, lower coral into it, shake off flatworms, remove. That's it. A lot more came off than I expected. Honestly I'm probably just going to get some flatworm exit at some point.