I have 3 of them, I put two in the live rocks and the other is laying on the bottom. they do just fine. What you're suppose to do is have them laying on the sand because I believe it feeds off of things on the sand and plankton as well. You can also bury the end of hem into the sand. I tried to bury one of mine in the sand the only problem was that the tube felt so fragile to me, it felt like it was going to tear, and I didn't want to tear it. Anywho, they are really cool.