Clown digging into sand

[GuyAFA]

My new (1 week) tomato clown has dug large holes in the sand about 6" in diameter behind a few of my rocks. So far the rocks seem stable but I'm concerned about my biofilter. Today it started diggin under the green star polyp that has been hosting it. Now the polyp is at the bottom of this hole. It's not as wide or deep as the first one.

Should I be concerned about this?:eek1:

 

[WaterbugJenn]

My maroon clown does the same thing. She now has an Lta nem to host in. I have asked this same question on this forum, and the only response I got was "Thats what they do". I have to continually back fill the hole around my Nem so she does not continually dig it up. As long as the clown can not cause an avalance of rock you should be fine.