Lawnmower blenny ?????

[pirate]

Well I'm tired of hand picking all the gha out of my tank, and was thinking about getting a lawnmower blenny. I like the way they look. Now for the questions. My gha is not totaly out of control yet but there is some so how much do I need for the little guy? I also have a pistol shrimp goby pair is this gonna be a problem? The other fish are a bengii and clowns. It's a nice peaceful tank and I want to keep it that way. Or is there some thing better at eating the gha? Crab, snail, what have you!

The tank is a 29g biocube setup as a reef.

I tried serching but could not find the answer I was looking for.