Have 2 yellow head gobies. They do great job of cleaning the sand. Can't say they've caused any damage other than sometimes having to push around the piles of sand they make. They also stay at the bottom so can't see them jumping out. But guess if there's a fish torturing them it's possible. When i first pit them in about 6mos ago they would make the water cloudy. Now not so much. Guess the fine floating particles got filtered out.
What size is your tank? Yellow heads need a large established sand bed. They will also make your tank very cloudy since they constantly sift. I have two conchs in my 93 cube that keep the sand very clean they are definitely the way to go.
I had a golden head sleeper gobie...
Most amazing worker i have ever seen, literally all day scooping sand and sifting it through his gills.
ALL DAY LONG..
Only problem with that was any corals on the sand bed get covered. Some clear them selves off others cannot.
But literally all day long until my Hippo chased him out of the tank.
My 4 conch have nothing on this guy!