Yup , there's three of them in my tank.
I've been sitting here in front of my tank trying to capture this odd behavior that they are pulling.
Occassionally, you'll see one of them jetting water into the rocks with its mouth for 10 seconds or so trying to uncover food. I've never read about them doing this in literature (then again, I haven't found very much literature on them, go figure), though I've seen triggers do it on TV.