Oh, then yes, I think some of it definitely is. I think there's a mix though, because there appears to be two different sites of rock in the mix. I know I love the rock though for sure, and I'm not sure I'm upset about the mantis. If he's a smasher and leaves fish and coral alone he can stay. I don't mind replacing the cuc occasionally.
And it's in the living room and dining room, so the noise didn't bother me. The clicking of the pistol and mantis shrimps is actually pretty calming to me. My wife likes it too, she was dozing off last night listening to it