Carpet anenome

[Delphinus]

Sorry I forgot about your question about the sand. In all honesty it will kinda go where it wants to anyhow but IME mine did prefer to hang out near the rock/sand interface. Actually now that I think about it, he attached to the bottom glass near a rock stand and dug the sand out of the way to do so.

If memory serves, sometimes when they are small (like <8" or thereabouts) they sometimes hang out higher up on rockwork but they eventually migrate down as they get bigger.