Do Zoanthids move themselves?

[techreef]

Hi everyone. I recently bought two 3-4" colonies of Zoanthus sp. Each colony is on a separate piece of liverock. Twice now I've found one of the colonies lying on the sandbed when I look into the tank in the morning. (they've been in my tank for 3 days)

Will Zoo's move themselves like anemones if they don't like their placement in the tank? Or is it a crab or something pushing the colony off the edge of the rocks that I've been placing it on?

[tgunn]

Zoas don't move on their own as far as I'm aware; certainly not once attached to a rock. I'd suspect something is pushing it over.

They will on occasion drop off a polyp which will anchor itself elsewhere in the tank. I've had that happen once in my system. I found a polyp poking out from the base of a liverock. Really surprised me.

[acrylic_300]

Hermit crabs really enjoy knocking rocks off of ledges.

[techreef]

I have what I think is a red xanthid crab which surprised me yesterday by sitting at the top of my liverock and staring at me as I worked around the tank. Totally unscared by me. The gorilla crab hitchhikers that I've been slowly eliminating are skittish as all get out. (Finally nabbed the last big one 2 nights ago. Yeah!) :) I thought the rocks that the zoo's were attached to would be big enough to resist getting pushed around, but I guess not. Thanks for the responses.